R e s e a r c h A r t i c l e H i s t o l o g ic a l a n d M o r p h o m e t r ic C h a n g e s in U n t r a u m a t i s e d R a b b i t S k e l e t a l M u s c l e T r e a t e d w it h D e e p T r a n s v e r s e F r i c t i o n . ABSTRACT: Deep transverse friction (DTF) is used in clinical practice and by its nature it may cause muscle injury. This study investigates the morphologic and morphometric changes in untraum atised rabbit skeletal muscle treated with DTF. M ethod: 16 New Zealand white rabbits were studied. The right vastus lateralis muscle was used as a control and the left vastus lateralis was treated with DTF. M uscle biopsies were taken 10 min, 24 h and 48 h after ] treatment, 48 h after 2 treatments and 48 h and 6 days after 3 treatments. Treatments were 48 h apart. Biopsies were prepared f o r light microscopy and tissue morphometry. Results: A fter 1 D T F treatment, intracellular and extracellular oedema was noted. Contraction bands seen throughout the fibres suggested severe mechanical trauma to the muscle. 48 hours after 1,2,and 3 treatments, the muscle appeared to be recovering with reduced oedema, and the contraction banding was limited to small fo c a l areas throughout each fibre. Six days after the last treatment, the myofibres, although normal in diameter, showed small fo c a l areas o f supercontraction and large internalised inclusion bodies composed o f a pool o f myofilaments or whorls o f membranous material. M orphometry showed oedema to be maximal immediately after treatment. Conclusion: D T F causes a severe but reversible injury to untraum atised myofibres. Its possible mode o f action in treatment o f injured muscle requires fu rth e r investigation. K E Y WORDS: DEEP TRANSVERSE FRICTION, SKELETON MUSCLE, LIG H T MICROSCOPY, MORPHOLOGY, MORPHOMETRY. DEANE M N , BSc (Physio), MMedSc (Sports M ed)1; GREGORY M A , PhD2; MARS M , MBChB3. 1 Lecturer, D e p t o f Ph y sio th erap y , U n iv e rs ity o f D u rb a n W estvifle. A ssociate Professor a n d H e a d o f th e Electron M ic ro s co p y U n it, U n iv e rs ity o f D u rb a n W estville. Professor, D e p t o f Physio logy, N e lso n R M a n d e la M e d ic a l School, U n iv e rs ity o f N a t a l. INTRODUCTION Deep transverse frictions (DTF) have been part o f the physiotherapists’ arm a­ m entarium for m any years. D espite its acceptance by practitioners there is little scientific evidence to support its use, and to date there has been no sys­ tematic review o f the efficacy o f deep transverse friction treatment. Further­ more, the treatm ent is painful and has potential to cause further damage. M enell advocated a specific form o f massage, called frictions, in the early C O RRESPO N D EN C E TO: Professor M Mars Departm ent o f Physiology Nelson R M andela School o f M edicine U niversity o f Natal Private Bag 7, Congella 4013 KwaZulu-Natal Tel: (031) 260-4364 Fax: (031) 260-4455 Email: m ars@ nu.ac.za 1900’s (Cham berlain 1982). In the mid seventies, C yriax and R ussel p o p u ­ larised the use o f a technique called deep transverse friction (DTF) massage, which provides therapeutic m ovement over a small area (Cyriax and Russel 1977). The potential advantage o f DTF is that it allows pressure to be applied at greater depths within muscle and it has been advocated for treatm ent o f muscle strains and tears, tenosynovitis, tendinitis and ligam ent sprains. A potential dis­ advantage is that sustained direct pressure on muscle is know n to dam age skeletal myofibres (Mars and Hadley 1998). One o f the key aims in treatm ent o f soft tissue lesions is to encourage the dam aged tissue to regain tensile strength as rapidly as possible (H unter 1994), with a flexible, functional scar (Dorman 1990). It has been po stu lated that D TF may achieve these goals through mechanical breakdown o f dam aged tis­ sue, traumatic hyperaem ia and induced analgesia (W inter 1968; C yriax and Russel 1977; Cookson and K ent 1979; Chamberlain 1982; Walker 1984; Kushner and Reid 1986). Through the application o f force transverse to the plane o f the m uscle fibres, it was proposed that after injury, deep transverse friction ‘spins’ or re-aligns the collagen fibres to their correct orientation (Stearns 1940). It has also been suggested that D TF breaks dow n and red u ces transverse and oblique fibrous adhesions that are part of normal scar form ation and that DTF can therefore assist in restoring full pain free mobility (G robbelaar 1991). This concept is not how ever supported by the histological evidence. In a rabbit model, D TF treated and untreated ligaments were found to have both longitudinal and random arrangem ent o f collagen fibres and it was concluded that D T F ’s do not have an effect on scar formation (W alker 1984). A ccording to N orris (1993), the purpose o f frictional m assage is to pro­ mote local hyperaem ia, reduce adherent 2 8 SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) mailto:mars@nu.ac.za scar tissue and induce massage analgesia. It is hypothesised that D TF causes a traumatic reactive hyperaem ia on an ischaem ic reperfusion basis (W inter 1968; Chamberlain 1982). The increased blood supply to the area may accelerate healing by increasing the supply o f nutrients to the injury site and rem oving m etabolites. Again the concept lacks clinical and experim ental support, as the reactive hyperaem ia will be o f relatively short duration. It has been shown that tourniquet induced ischaem ia for 90 min is associated with a reactive hyperaemia that last approximately 15 min (Mars and Brock-U tne 1991). It is hypothesised that D TF induced massage analgesia maxim ally stimulates m echanoreceptors causing the release of neuro-peptides that inhibit and over­ ride conduction of pain relayed from nociceptors in slow pain fibres (LeBar et al 1979; de Bruijn 1984). The histological effects o f D TF on skeletal m uscle have not been docu­ mented. In order to interpret the histo­ logical changes that occur following DTF treatm ent o f injured m uscle it is necessary to first docum ent the changes produced in untraum atised muscle. The aim o f this pilot study was to serially exam ine the histological and morpho- metric changes produced by D TF treat­ ment in untraumatised skeletal muscle. METHODS Sixteen New Zealand, w hite rabbits were studied with the approval o f the Ethics and Research Com m ittees o f the U niversity o f Natal and the University o f Durban Westville. The animals were h oused in the B iom edical R esource C en tre (B R C ) o f the U niversity o f Durban W estville and were m aintained under the care o f the staff o f the BRC. T he animals were fed ad libitum and w eighed before each treatm ent session as w eight loss may be associated with muscle atrophy. B efore each treatm ent anaesthesia and analgesia were achieved by an intra­ m uscular injection o f a com bination o f 50% Ketam ine and 50% Xylazine, lOmg/kg o f rabbit body weight. The treat­ ment area was the left vastus lateralis at the level o f the m id-thigh and the fur was rem oved with a depilatory to facilitate observation o f any inflam m a­ tory reaction and to facilitate treatment. To ensure that treatm ent was applied at the same point, the treatment site was clearly m arked with indelible ink. Treatm ent consisted o f 10 min of deep transverse friction using the index finger. A fter treatm ent the anim als were observed during recovery from the anaesthetic and then returned to the holding facility. Eight anim als underw ent a single treatment, with m uscle biopsies being taken 10 min after treatm ent (n = 2), 24 h after treatm ent (n = 2) and 48 h after treatm ent (n = 4). Four animals underw ent 2 treatm ents, w ith 48 h between treatments, and all were biop- sied 48 h after the final treatment. Four animals underwent 3 treatments, with 48 h between treatm ents and biopsies were taken 48 h after the final treatment (n = 2) and 6 days after the final treat­ ment (n = 2). The tim ing o f the biopsies was based on previous animal studies and was designed to show the spectrum o f m uscle changes from treatment to repair at 6 days. Control biopsies were taken from the right vastus lateralis muscle in 4 animals. Muscle Biopsy and Preparation Before m uscle biopsy, the animals were anaesthetised and then euthanased. The skin was incised longitudinally over treatm ent site. The fascia was opened and a biopsy o f approxim ately 1cm3 of vastus lateralis m uscle excised from the treatm ent site. To reduce biopsy induced, “supercontraction” artefact of the muscle, the entire biopsy was im m e­ diately im m ersed in fresh K am ovsky’s fixative as per the m ethod o f Olmesdahl et al, 1979. After 5 m inute immersion, the biopsy was bisected, one segm ent being im m ersed in 10% formal saline, dehydrated through graded ethanols, cleared in xylene and em bedded in wax for histology and morphometry. The other segm ent was minced into appro­ xim ately 1mm cubes and re-im m ersed in fresh K am ovsky’s fixative. There­ after, the tissue was osm icated in 1% osm ium tetroxide, dehydrated through graded ethanols and em bedded in Spurr epoxy resin for high resolution light microscopy. Light Microscopy & Morphometry Sections o f 3 |jm were cut off the wax em bedded tissue w ith steel blades and thereafter stained for haem atoxylin and eosin (H and E) using a Satura Diversified Stainer. The sections were exam ined using a light microscope with a 10X objective. T he m orphom etric m ethod used was that described by M ars and Gregory (1991). In brief, suitable areas containing transversely sectioned myofibres were selected for m orpho­ metric evaluation. T hese were then displayed on the m onitor o f a m icro­ com puter by means o f a video cam era interfaced w ith the m icroscope. The myofibres were considered to be near cylinders and the diam eter o f trans­ versely sectioned fibres was taken to be the m inim um distance across the fibres. This distance was m easured for each fibre by positioning two cursors on the m uscle fibre im age and the com puter software calculated and stored the m ea­ surem ent. A m inim um o f 100 fibre diam eters o f each specimen was m ea­ sured in each o f the H and E stained sections. The mean and standard devia­ tion w as d eterm ined fo r the fibres within each animal and for each group of animals. Com parisons o f means w ith­ in and between groups were by analysis o f variance with post hoc testing using the Tukey-K ram er test. For intra-group com parisons o f groups containing two sets o f data, a two tailed unpaired T-test was used. The Chi square test was used to test differences in fibre distribution contingency tables. Significance levels for both tests were set at, p < 0.05. RESULTS The average weight o f the rabbits prior to the first treatm ent was 2.74 ± 0.34 Kg and the average change in weight between treatm ents o r between treatm ent and biopsy was less than 1 g with a range of 7 g gained (3.7 %) to 9 g lost (4.2 %). There was obvious reddening o f the skin o f animals im m ediately after DTF and this was still apparent 24 hours after treatment. The inflammation disappeared within 48 hours o f DTF. Follow ing DTF treatm ent m uscle turgor on palpation was increased. M uscle biopsies taken from control muscles were noted to bleed less than SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 2 9 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Table 1: Mean morphometric data o f individual specimens, and the mean and standard deviation o f each group of biopsies expressed in pm, from biopsies taken after 1 (1 T), 2 (2 T) and 3 (3 T) treatments. Specimen No. Control IT: 10 min 1 T: 48 hrs 2 T: 4 8 hrs 3 T: 4 8 hrs 3 T: 6 days Biop 0 hr Biop 4 8 hr Biop 48 hr Biop 4 8 hr Biop 6 d ay 1 56.1 64.1 58.2 51.7 58.4 56.1 2 55 61.8 63.2 56.4 51.7 51.4 3 53.6 61 4 8 .4 4 49.4 58.7 59.8 Mean 53.5 63.0 60.3 54.1 55.05 53.8 SD 2.9 1.6 2.3 2.3 4.7 3.3 Max. 56.1 64.1 63.2 59.8 58.4 56.1 Min. 49.4 61.8 58.2 48.4 51 .7 51.4 Table 2: The distribution of skeletal myofibres based on m yofibre diameter, after various periods o f treatment, expressed as a percentage, and as the mean, standard deviation (SD), and m axim um and minimum diameters. Fibre Group Control IT - lOm in IT - 4 8 h 2T - 48h 3T - 48h 3T - 6days Biop 0 hr Biop 4 8 hr Biop 48 hr Biop 48 hr Biop 6 d a y < 20 pm 0.6 1 0.5 0.7 0 0.5 21 - 30 pm 8 4 4 5 5 8 31 - 4 0 pm 14 7 11 18 14 15 41 - 5 0 pm 21 13 18 21 23 24 51 - 60 pm 22 18 18 26 27 22 61 - 70 pm 20 24 18 15 14 12 71 - 80 pm 9 15 17 12 12 9 81 - 90 pm 4 10 9 3 6 7 91 - 100 pm 1 7 3 0.3 0 0.5 101 -110 pm 0.5 1 2 0 0 0.5 EoA 0 0.5 1 0 0 1 Mean (pm) 53.9 62.8 60.5 53.4 5 4 .7 53.8 SD (pm) 16.4 18.8 19.1 15.3 15.2 18.1 High (pm) 108 121 131 100 87 113 Low (pm) 16 18 20 18 23 17 N o Fibres 341 217 343 413 160 200 N o of Specs. 4 2 4 4 2 2 D TF treated muscle. M uscle biopsied im m ediately after a single treatm ent appeared to be darker in colour, consis­ tent with local haemorrhage. Histology and Morphometry M yofibres in control tissue appeared as irregular polygons grouped into bundles (Figure 1). The morphom etric data of individual specim ens from each D TF therapy group is shown in table 1. Note that in control specimens, all means were within the range 49.4 |jm to 56.1 |jm . In both groups receiving 1 D TF treatment (IT ) and biopsied 10 min and 48 h after treatment, the means o f all specimens were greater than control values. In the case o f 2T: 48 hours and 3T: 48 hours, while group mean values were within the normal range (54.1 |jm and 55.05 |jm respectively), 50% o f the specimens in each group had means above normal values. Six days after 3 D TF treatments, the diam eters o f m yofibres in both specimens were within normal values. The mean morphometric data o f the individual samples are shown in Table 2. Fibre diam eters in controls and all treatm ent groups ranged from 16 |jm to 131 |jm . Significant differences in the distribution o f fibre diameters, (p < 0.05) were shown between controls and biop­ sies taken 10 min and 48 h, after a single treatm ent (Figure 2). The distribution o f fibre diam eters was similar to the con­ trols. Comparison o f mean diam eters by ANOVA shows a significant difference (p = 0.038) with the greatest difference between the controls and the biopsies taken im m ediately after one treatment. However, post hoc testing did not reveal significant differences between groups. 3 0 SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Figure 1: Light m icrograph o f 5 pm w a x embedded, haema- toxylin and eosin stained section showing cross-sectioned myofibres (F) in norm al ra b b it skeletal muscle. The arrow s m ark the diameters o f fibres used fo r m orphometry. Figure 3: 10 minutes after 1 DTF: LM o f 1 (m toluidine blue stained, resin embedded section show ing numerous supercon­ traction bands (C) through the full thickness of the muscle fibre. M = m yofibrils. Figure 2: Bar histogram showing the distribution of fib re diameters in control muscle and tissue, 10 minutes and 4 8 hours after 1 DTF treatment. Note shift o f myofibres to larger diameters after 1 DTF. <20um 21-30um 31-40um 41-50um 51-60um 61-70um 71-80um 81-90um 91-100um 101-1 lOum c llO u m Range of fiber diameters (um) Light Microscopy of 1 pm Toluidine Blue Sections The tissue was orientated and sectioned in such a m anner as to enable the longi­ tudinal aspects o f m yofibres to be examined. Control specimens showed m yofibres w ith regularly arranged myofibrils with peripheral, elongated oval nuclei. There was no evidence of intercellular or intracellular oedem a and there were no inflammatory cells in the interfibre spaces. Ten minutes after 1 treatment, numerous densely staining, super-contraction bands were observed extending vertically through the dia­ m eter o f most myofibres (Figure 3). In some instances, myofibrils appeared to have separated from one another and had become disorientated. The fibres were separated by larger spaces suggesting intercellular oedema. There were no obvious differences in the m orphology o f m yofibres in specimens taken 48 hours after 1, 2 or 3 DTF treatments. In all cases the contrac­ tions, while still present, were smaller and restricted to a few myofibrils, espe­ cially those beneath the sarcolem m a (Figure 4). The m yofibres appeared less separated, 48 hours after each treatment. Six days after 3 treatments, there was minimal evidence o f contraction band­ ing which, when present, was exclusively SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 31 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Figure 4 : 4 8 hours after 1 DTF: LM o f 1 (m, toluidine blue stained, resin embedded section showing occasional peripheral and internal contraction bands involving up to 4 sarcomeres (arrowed). N = nucleus. Figure 5: 6 days a fte r 3 DTF: LM o f 1 (m, toluidine blue stained, resin embedded section showing large, amorphous inclusions w ith in the fibre (AIB and arrows). Note absence o f contraction bands in these fibres. Figure 6: 6 days a fte r 3 DTF: LM o f 1 (m, toluidine blue stained, resin embedded section showing large inclusion bodies com­ prised o f membranous w horls (MIB and arrows). Note the absence o f contraction bands in the fibre. restricted to the periphery. The most striking anomaly was the presence o f large inclusion bodies near the centre of fibres. Some were particularly toluidine blue positive while others were pale and appeared to contain filam entous structures (Figures 5 and 6). Intercellular spaces had returned to those seen in control specimens. DISCUSSION T he m orphom etric and histological results show that DTF causes myofibre oedema. Shortly after treatment, myofibres had increased in diam eter and although not quantified, there appeared to be an increase in interfibre spaces. There were, however, some anom alies in the results from the groups o f specim ens taken 48 hours after DTF. W hile there was a non-significant increase in group mean fibre diam eters (GMD) 48 hours after 1 treatment, there were no apparent differences in GM D 48 hours after 2 and 3 D TF treatments. Closer exam ination o f the data from each specim en showed that 50% o f the samples in each group were larger than those in the normal range (Table 1). There is a reduction in myofibre oedema 48 hours after DTF, and 6 days post DTF the m yofibres have returned to control dimensions. Control m uscle appeared normal when viewed by light microscopy. No contraction bands were present, indicating that the preparation o f tissue after the biopsy procedure had not caused m echanically induced contraction bands (Olm esdahl et al 1979). The m orphological results showed that DTF, caused rapid change in m yofibre structure. Shortly after DTF, the m yofibres exhibited severe supercontractions throughout the full length o f each cell. In addition, there was evidence of m yofibril disorganisation and displacem ent. Irrespective of the num ber o f DTF treatm ents, 48 hours after treatm ent super­ contractions were reduced and limited to focal areas, especially near the periphery o f fibres. Six days after DTF, super­ contractions were limited to occasional groups o f supercon­ tracted sarcom eres on the periphery o f fibres. However, o f particular interest were the two types o f inclusion seen in many fibres. The first type o f inclusion appeared pale in toluidine blue stained sections and contained what appeared to be membranous fragm ents, while the second type were darkly stained and appeared to contain m yofibrillar elem ents (actin and myosin filaments). T hese are particularly significant observations indicating that DTF causes a serious, albeit reversible injury to skeletal myofibres. No other abnorm alities o f the myofibres were noted. M uscle injury is caused in m any ways and expressed by m any and varied morphological changes within myofibres and connective tissue. The changes caused by controlled injury have been described in several animal models and are considered to reflect injury and reparative processes in man. Stretch-induced injuries in rabbit skeletal m uscle are m arked by “disruption” and haem orrhage within the m uscle (Nikolaou et al 1987). Friden et al (1983a) showed that there was microscopically identifiable disruption o f myofibrils and stream ing o f Z line in injured human muscle. In another study, electron microscopy showed significant changes in the sarcomeres o f overstrained vastus lateralis m uscle in cyclists (Friden et al 1983b). 32 SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) In a rabbit model, Reddy et al (1991) found that 1 hour after injury “torn” fibres had supercontracted sarcomeres within 100 |jm o f the rupture site, both proxim al and d istal to the injury. Sarcom ere length gradually increased with distance from the rupture site with normalised at a distance o f approxim a­ tely 500 |jm . Supercontraction is a com m on feature o f m uscle injury and is thought to be a consequence o f massive calcium release from the sarcoplasmic reticulum or influx o f calcium through the sarcolemma. The following is a postulate o f how DTF may encourage m uscle healing. Mechanical stimuli have been shown to alter cellu lar functions including ion transport and protein synthesis (Schw artz et al 1991). It is suggested that following DTF, there is a significant increase in blood flow to the muscle (W inter 1968; Cham berlain 1982; de Bruijn 1984; Walker 1984; K ushner and Reid 1986; Norris 1993). In addition to hyperaem ia, this study show s that DTF causes a reversible m uscle injury, which initiates an inflammatory response expressed in the form o f m uscle and m yofibre oedem a and m yofibre super­ contraction. That DTF causes myofibre oedem a has been reported by Prentice and Bell (1990) who suggest that “mas­ sage appears to facilitate tissue repair by inducing and reducing oedem a through the pressure that provides the initial stimulus for the healing cascade” . Perhaps this additional injury to already dam aged m uscle increases the tissue cytokine response and thus the “natural” inflam m atory response, thereby attract­ ing the necessary phagocytes, other inflam m atory cells to the dam aged area. Concentrating these moieties at the site o f injury may facilitate rapid healing. On the other hand DTF may not be enhancing the inflammatory cascade but may be slowing healing by the addition o f an iatrogenic injury to already trau- m atised tissue. This pilot study shows that DTF alters m uscle and myofibre structure at the macro- and m icroscopic level. There are, however, many unanswered ques­ tions. A re the d ifferen t fib re types affected to the same extent by DTF with regards oedema and pathom orphology? How oedem atous does muscle becom e after DTF and what is the natural time course o f the return to norm ality? W hat ultrastructural changes occur in m yo­ fibres exposed to DTF and what are the inclusion bodies seen 6 days after treatment com posed of? Further studies em ploying histochem istry, m orpho­ metry and transm ission electron micro­ scopy are required to answ er these questions. CONCLUSION The results o f this study show that deep transverse friction causes m orphological changes in normal, rabbit skeletal m us­ cle fibres. Myofibres become oedematous shortly after D TF and they develop supercontraction bands. These are cha­ racteristic o f m uscle injury. The severity o f injury reduces with tim e showing that injury caused by DTF is reversible. It is postulated that DTF may prom ote healing by causing an additional inflam ­ matory reaction which triggers a cascade o f healing responses thereby shortening healing time. It may also be o f no bene­ fit and merely add to the existing injury. Further studies are required to determine the mode o f action o f deep transverse friction therapy. ACKNOWLEDGEMENT: T his study was funded in part by grants from the South African Society of Physiotherapy and the U niversity o f Durban Westville. REFERENCES C h a m b e rla in G L 1982 C y r ia x ’s frictio n m assage: a review. Journal o f O rth o p a ed ic and S ports Physical T herapy 4:16-22 C ookson J, K ent B 1979 O rthopaedic m anual therapy: an overview . Physical T herapy 59: 136-146 C yriax J, R ussel G 1977 T reatm ent by m anip­ ulation m assage and injection. In: Textbook o f O rthopaedic M edicine, C yriax J (editor). W illiam s and W illiam s, B altim ore: 18-36 De B ruijn R 1984 D eep transverse friction: Its analgesic effect. International Journal o f S ports M edicine Suppl 5: 35-36 D orm an P 1990 T he sig n ific a n ce o f scar tissue on re h abilitation o f the athlete. Sport and H ealth 8:17-19 F riden J, S eger J, Sjostrom M , E kblom B 1983a A daptive response in hum an skeletal m u sc le su b je c te d to p ro lo n g e d e c c e n tric tra in in g . In te rn a tio n a l Jo u rn a l o f S p o rts M e dicine 4 : 17 7 - 183 F rid e n J, S jo stro m M , E k b lo m B 1983b M y o fib rilla r d a m a g e fo llo w in g in te n se e c c e n tric e x e rc is e in m an. In te rn a tio n a l Jo u rn a l o f Sports M e dicine 4 :170-176 G ro b b e laa r C 1991 T he clinical effectiveness o f deep transverse friction in the treatm ent o f acute m uscle injuries in sports. (T hesis, C ape Town) H unter G 1994 Specific soft tissue m o b ili­ sations in the treatm ent o f soft tissue lesions, Physiotherapy 80: 15-21 K ush n er S, R eid D 1986 M a n ipulation in the trea tm e n t o f ten n is elbow . Jo u rn a l o f O rth o p a e d ic S p o rts P h y sic a l T h e ra p y 7: 264-272 L eB ar D, R ivot JP, G u ilb an d G, M enetrey D, Bessen JM 1979 T he de p ressiv e effects o f m orphine on the C fibre re sp o n se o f doresal horn neurons pretreated or not by pCPA . B rain R esearch 176:337-353 M ars M , B rock-U tne JG 1991 T h e e ffect o f to u rn iq u e t re le a s e on in tra -c o m p a rtm e n ta l pressure in the b a n daged and u n b andaged limb. Journal o f H and Surgery - B ritish 16: 318-322 M ars M, G regory M A 1991 A histom etric analysis o f skeletal m yofibres fo llo w in g 90 m in o f to urniquet ischem ia and reperfusion. Journal o f Surgical R esearch 50: 191-195 M ars M , H adley G P 1998 R aised intracom - partm ental pressure and c o m p a rtm e n t sy n ­ drom es. Injury 29: 403-411 N ikolaou P, M a c D onald B, G lisson R, Seaber A, G a rrett W 1987 B iochem ical and h isto lo ­ gical evaluation o f m uscle a fter controlled strain injury. A m e ric an Jo u rn a l o f S p o rts M edicine 15:9-14 N orris C 1993 Sports Injuries. B utterw orth H einem ann, N ew York: 109-111 O lm esdahl PJ, G regory M A , C am eron E W J 1979 Ultrastructural artefacts in biopsied normal m yocardial biopsy in m an. T horax 34:82-90 Prentice W E , Bell G W 1990 P athophysiology o f m u sculoskeletal injuries and the healing p ro c ess. In: R e h a b ilita tio n T e c h n iq u e s in S ports M edicine, T im es M irror, St. Louis R eddy A, Reedy M , B est T 1991 E valuation o f strain injuries in rabbit skeletal m uscle using a single fibre m odel. Surgery Forum 12: 44 S c h w a rtz M , L e c h e n D , In g b e r D 1991 F ib ro n e c tin a c tiv a te s the N A /H a n tip o rt by inducing clu ste rin g and im m obilisation o f its re c e p to rs , in d e p e n d e n t o f c ell shape. P ro c e e d in g s o f the N a tional A c ad e m y o f Science 88: 121-122 S tearns M 1940 S tudies on the de v elo p m en t o f connective tissue in transparent cham bers in the ra b b it’s ear. A m erican Journal o f A natom y 67: 55-97 W alker J 1984 D eep transverse frictions in lig a m e n t h e alin g . Jo u rn a l o f O rth o p a e d ic Sports Physical T herapy 6:89-94 W inter D 1968 T ransverse frictions. Physio­ therapy 24:5-7 SA J o u r n a l o f P h y s io t h e r a p y 2002 V o l 58 No 1 3 3 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. )