THE CONSTRUCTION AND EVALUATION OF A LOW-COST ISOKINETIC KNEE EXERCISER David Greenblatt* Summary An inexpensive knee exerciser which closely approximates the perfor­ mance of state-of-the-art isokinetic equipm ent has been constructed and a preliminary evaluation has been carried out. Unlike other exer­ cisers, the lower lim b angular velocity cannot be set a priori but, on the basis of patient performance it is possible to restrict lim b velocity to within upper and lower bounds. The exerciser makes use of a shock absorber and lever mechanism which allow easy calibration of the system while elementary electronics and computer interfacing allow the measurement angle, velocity and torque in real time. A significant advantage of this exerciser over some isokinetic knee exercisers currently on the market is that limited arc rotation can be enforced. This type of lim b restriction is important in many rehabilitation pro­ grams. Opsomming 'n Lae koste knie oefenmasjien wat die werkverrigting van huidige vooraanstaande isokinetiese masjienerie nou naboots was gekon- strueer, en voorlopige toetse is gedoen. Anders as ander masjiene, kan die rotasie snelheid van die onderste ledemaat nie a priori verstel word nie, maar 'n m inim um en maksimum perk kan gehandhaaf word soos bepaal deur die pasient se krag. Die oefenmasjien maak gebruik van 'n skokbreker en hefboom meganisme wat kalibrasie vergemaklik. Eenvoudige elektroniese en rekenaar koppeling m onitor die hoek, snelheid en wringkrag terwyl die masjien in gebruik is. Hierdie masjien het ’n aansienlike voordeel bo vele ander isokinetiese knie oefenmas- jiene in gebruik omdat die rotasie hoek van die ledemaat beperk kan word soos verlang. Di6 beperking van die ledemaat is belangrik vir baie rehabilitasie programme. Key words: low-cost, isokinetic knee exerciser, shock absorber/lever mechanism, computer interlacing, limited arc rotation. INTRODUCTION Ever since isokinetic exercise was introduced by Thistle et all it has been widely used for research, clinical testing and rehabilitation, and has become an indispensable tool in the field o f sports science. The main advantage o f this type o f exercise over other modes is that it allows the development o f maximal muscle tension throughout the range of limb motion (see Thistle et a? and Hislop and Perrine^). Exercisers o f this kind currently on the market include the highly sophisticated electro mechanical Cybex system which is capable of exercising many body joints, while hydraulics-based systems such as the Orthotron KT series are used exclusively for knee exercise and rehabilitation. For many years, South African physiotherapists have been aware of the important and essential role that isokinetic exercise plays in physical rehabilitation and injury assessment. It is unfortunate, how­ ever, that the cost o f importing and maintaining isokinetic testing and rehabilitation equipment is prohibitive, and this limits its availability in the country. During late 1990 it came to the attention o f South African physiotherapists that the Bioenergetics o f Exercise Research Unit (B E R U ) at the University o f Cape Town (U C T ) are “conside­ ring the development o f an isokinetic unit which will be calibratable, give reproducible results over the entire range of movement and will measure torque and angle simultaneously in real time”. An inexpensive knee exerciser o f this type has recently been developed privately and has been tested at the University of the W itw atersrand M ec h a n ic a l E n g in ee rin g L ab oratories. It will be shown in the forthcoming sections o f this paper that the exerciser closely approximates the isokinetic principle for a fraction o f the cost o f overseas exercisers and fulfills all o f the requirements set down by the BERU . PRINCIPLE OF OPERATION An ideal isokinetic exerciser will allow the patient's limb to move at a constant velocity irrespective o f the torque developed. This is achieved, for example, with the Orthotron by means of pressure compensating values. Another less obvious method o f achieving isokinetic motion is to determine a priori the patient's torque versus angle characteristics and then set up the system response so as to bring about isokinetic motion.3 The problem o f designing such a system is greatly simplified if it is assumed that the torque versus angle characteristics for all patients can be characterised by a certain family o f curves. By considering the results from a large cross-section o f patients, it is evident that for both extensor and flexor muscles of the knee, torque is at a minimum at the fully extended and flexed positions and reaches a maximum somewhere in-between. This type o f result is shown in figure 2 with reference to the nomenclature of figure 1. I Fig 1: Nomenclature for the knee position during isokinetic exercise The exerciser that is described here may be configured to-m atch the torque versus angle characteristics o f the patient in one direction, and consequently bring about isokinetic motion of the limb in either extension or flexion. This may also be achieved to an acceptable degree o f approximation for exercise in both directions (see section 4). Figure 3 is a schematic representation o f the exerciser mechanism where OB is the lever arm, AC is the position o f an hydraulic shock absorber and the points O and C are stationary. The lower leg of the BSc, MSc (Mechanical Engineering), University o f the Witwatersrand CSIR, P O Box 395, Pretoria 0001 Physiotherapy, May 1992 Vol 48 no 2 Page 15 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. ) BOSCH DYNOMED M For pain therapy and vegetative changeover, DYNOM ED M offers m edium -frequency currents, ultra-stim ulatory current, and direct current. Also available for rehabilitation are two pulse currents and two m odulated swelling currents. Bipolar current application is advantageously performed. The medium frequency currents can also be applied in single-phase mode, ie. with a galvanic com ponent for m etabolic stimulation. The DYNOM ED M unit is equipped with an alpha-num eric LCD display for dose and treatm ent duration. The display also gives control instructions. Current form s DYNOMED M * 6 medium frequency currents: * Max. patient current 60mA s (at patient 1-10 Hz, 10-25 Hz, 25-50 Hz, resistance of 1.5 kQ) 50-100 Hz, 80-100 Hz, 100-200 Hz; * Treatm ent duration max. 30 min * triangular pulse currents (D): * Treatm ent time and dose/ 150 ms: 1 s, 250 ms: 1 ,5 s control instructions display 16-digit LCD (pulse duration: pause duration); * Dimensions W X D X H: * modulated swelling currents (MOD): 33 X 24 X 8.5 cm 5:20 ms, 0,5:20 ms, * Weight around 1.8 kg modulation: 4 s (2:1,3:0,7), pause duration: 4 s; * Protection class II, according to * ultrastimulatory current (Trabert) (UR): 2:5 ms; DIN IE C 601/VD E 0750, part 1 * GS safety approval mark of the Berlin TUV. A c c e s s o rie s DYNOMED M is supplied complete with standard accessories. It contains: mains connection cable, one pair of plate electrodes PEL 50 (=50cm) with sponge pockets, one 2-pole electrode cable, two perforated rubber straps each 40 and 135cm long with closures. MARKETED & SERVICED BY: £ Clinical EiMfgcncte/ (PTY) LTD4EDMS) BPKn«g no n m t w Tel: (011) 613-8114/Cape Town (021) 89-1046/Pietermaritzburg (0331) 94-8977 Cnr Outspan & Fortune Streets, No 6 Old Mutual Industrial Park, City deep. P.O.Box 11083, Johannesburg 2000 E asy to operate, lightw e ig ht a n d transporta ble P ola rity re ve rsa l a vailable at the touch of a button Dust-tig ht washable foil k ey bo a rd Vacumed D. B i- polar suction unit also a vailable 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. ) Angular Displacement (6) Fig 2: Typical torque versus angle characteristics for the knee joint patient applies a torque Tp to the lever arm. Now the relative position of C to O can be adjusted so as to locate the position of maximum torque developed by the patient at 0 = 9 0 ° . In so doing the patient is required to move the shock absorber through its maximum displacement relative to the limb motion in the region of maximum torque. It is an easy matter to show, and indeed intuitive, that the shock absorber resists with maximum force at this point when the motion is isokinetic. The magnitude o f the resisting force, relative to the force of the patient, can then be set by suitably adjusting points A and C or by adjusting the damping capacity of the shock absorber. In this manner the patient’s lower leg can be varied through a spectrum of velocities. CONSTRUCTION AND MEASUREMENT The exerciser constructed for this study made use of a chair similar to that used for the Orthotron. The Orthotron hydraulic assembly, however, was replaced by a shock absorber and lever assembly such as that shown in figure 3. The shock absorber had three settings corresponding to three different damping coefficients and the positions A and C were adjustable relative to O. This allowed the patient to traverse the entire range of lower leg motion and, in addition, arbitrary limited arc rotation could be enforced by suitable adjustment of positions A and C. It is important to note that this latter feature, which is often required in routine rehabilitation pro­ grams, is not available on the Orthotron KT series. The mechanism itself occupied a little less volume than the KT2 hydraulic actuator and a patient could easily vary the settings while remaining com fort­ ably seated. Consequently, no bulkiness problems arose. For the angular displacement (or angle, 8) versus time measure­ ments conducted on the exerciser potentiometers, connected in wheatstone bridge configurations, were fitted to the left and right leg shafts at O. These were then interfaced with an IBM computer via a computer scope. A calibration of the experimental setup showed a linear response of bridge voltage output as a function o f 6. The differential equation governing the motion o f the exerciser was derived by da Silva and Greenblatt.3 For this analysis a substan­ tially simplified approach was adopted in which it was assumed a priori that the motion of the exerciser was isokinetic. This allowed considerable simplification of the governing equation giving rise to a quasi-isokinetic analysis. Using this analysis the torque developed by the patient can be expressed as q)c' / 2Vd 2 + J 2cos(9 - P) sili <(> T A Q) - ( l 2 + D 2 + d 2 - 2/V£>2 + d 2stn(9 - P))° where a> is the angular velocity o f the lever arm and c is the linear damping coefficient o f the shock absorber. The other quantities are defined in figure 3. Details o f this derivation are given by da Silva and Greenblatt. For calibration purposes the damping coefficients of the shock absorbers were determined for both extension and com ­ pression strokes by a simple "load and time” technique. Although this system is fairly complex geometrically, it is pointed out here that the dynamics of the system are not difficult to characterise mathe­ matically. Consequently, with the geometry o f the system and the damping coefficient of the shock absorber known, it was not a difficult task to calibrate the system. RESULTS AND EVALUATION 8 3Q.V) S M time (seconds) Fig 4: Angular displacem ent versus tim e plot fo r patient A - right leg The exerciser was evaluated using a female “patient” and a male “patient" who are referred to henceforth as patient A and patient B respectively. Both patients were in their early twenties when this evaluation was carried out. In all tests performed, both legs were exercised simultaneously, with one leg flexed and the other extended and vice versa, as this proved to be just as convenient as exercising one leg at a time. An example of the angular displacement versus time plot for the right leg o f patient A is presented in figure 4. The left leg result is almost identical and consequently is not presented here. In order to achieve the result presented in the figure, the geometry of the exerciser was configured, on a trial and error basis, to ensure iso- Physiotherapy, May 1992 Vol 48 no 2 Page 17 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. ) WCPT PRIVATE PRACTITIONERS INTERNATIONAL MEETING, HONG KONG 1992____________________ £ C L I N I C A L C O R N E R by Clinical Emergencie/ Clinical corner is a special offered by Clinical Emergencies to promote products used by physiotherapists. This offer is valid for the specified month only. BOSCH DYNOMED (Medium Frequency Unit) Now reduced to only R3380,00 JUNE ~ For placing of orders, delivery or any additional information please contact Lawrence Kimble at (011) 613-8114 S P E C IF IC A T IO N S • 6 medium frequency currents • Triangular pulse currents • Modulated swelling currents • Ultrastimulatory current • Direct current • Portable - 1 ,8skg WCPT announces an exciting new con ­ cept for an international meeting. K ey -n o te sp e a k e r s from all over the world 'will set the scene and lead the debate in various crucial topical areas of Private Practice. A series o f workshops around these themes will follow where delegates will be encouraged and expected to be par­ ticipatory. Hong Kong was chosen as a venue as being equidistant from the major countries who will be interested in the meeting, and therefore hopefully the cost should not be disadvantageous to any o f the WCPT Re- gions.lt has been possible for WCPT to keep the registration fe e for a five-day meeting down to the equivalent of $400. The Meeting will be opened by the Rt Hon David I.,angc, ex Prime Minister of New Zealand, setting the scone on interna­ tio n a lis m . T h e m ain s e s s io n s are th en taken by leaders in the fields o f physical therapy and business: Diana I f t : Weakness and Strength I'om Arild Torstcnsen: Rehabilitation in Sport and Workplace Brian Mulligan: Cervical Issues Mike l^imonl: Information Systems Ray Dillon: business of 1 Iealthcare in the Future Specific initiatives agreed upon for the period until the next meeting: • Thai WCI’T should continue * its co-operation with the Interna­ tional Institute on Aging (United Nations) - Malta * its c o -o p e r a tio n with the W ordl Health Organisation to produce a text on the care of children with C e r e b r a l P a ls y in D e v e l o p in g Countries * it co-operation with WHO and the W o r ld F e d e r a t io n o f O c c u p a ­ tio n a l T h e r a p is ts on policy for Community Based Rehabilitation George Beaton: Markets and Marketing for Private Practices. WORKSHOP DETAILS A. Management o f Instabilities Diane Lee B. Manipulation Lance Twomey C. Competitive Advantage through Human Resource Management Margaret Beaton D. Presentation of Selected Papers E. Ergonomic Physiotherapy Practice Tom Arild Torstensen F. Sports Physiotherapy Graham Neil Smith G. Health Politics/Funding for Health Michael Lamont H. Blending Quality and Profit Ray Dillon Papers are now being solicited for a few refereed papers, and those interested in submitting an abstract should contact Ca­ therine McGinley in Canada (Fax: (1) 403 284 1976). R e g istra tio n b r o c h u r e s for atten ding the Meeting are available form the Private P ra c titio n e r s A s so c ia tio n (M r Chris de Wet, (O il) 726-5466). a n d th e tr a in in g o f M id -L e v e l Workers * to c o n sid e r the possibility o f an international research review type journal * to r e v ie w its p u b lic a t io n p r o ­ gramme * to c o -o p e r a te with in tern ation al agencies such as Rehabilitation In­ ternational and the International Council on Disability, United N a ­ tions, and the WHO on a consult­ ative basis • That WCPT should set up a Task Force on Standards K F O R P Physio Forum Is th e m agazine fo r ph ysio th e ra p ists w ho w ant to keep up to date w ith th e latest • courses • lectures • books • branch news • NEC a ctivitie s • Back Week • P hysiotherapy Week • p o s itio n s available • p ro d u c ts and equipm ent. S ub scrib e now! The fee s are • R30 (incl VAT) fo r SASP m em bers • R66 (incl VAT) fo r non-m em bers N on-m em ber s u b s c rip tio n s may be posted to P hysiotherapy P ublications, P O Box 695, Edenvale 1610; E nq uiries (011) 485-1457) WCPT: 72ND EXECUTIVE COMMITTEE MEETING FEBRUARY 1992 Bladsy 18 Fisioterapie, M ei 1992, deel 48 no 2 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. ) time (seconds) Fig 5: Angular displacement versus tim e plot for patient A - right leg, one cycle S 9 a I time (seconds) Fig 6: Angular displacement versus tim e plot for patient B - left leg, one cycle kinetic motion for both extension and flexion. This is more clearly illustrated in figure 5 where only one extension and one flexion arc considered. In this figure, linear curves' have been superimposed on the exerciser data for both extension and flexion. These linear curves represent perfect isokinetic motion. It can be seen that for almost the entire range o f lower leg motion, deviations from the isokinetic ideal are negligible. It is only at the extremities i.e. near 0 to 90 degrees, that significant departures from isokinetic motion are evi­ dent. These deviations are to be expected since it is impossible to physically achieve perfect isokinetic motion, as this would require infinite accelerations of the limbs at the extremities. Data for the left leg o f patient B, in the same format as figure 5, is presented in figure 6. Once again isokinetic motion was achieved for both flexion and extension by suitable adjustment o f the exerciser geometry. It should be noted, however, that the shock absorber/lever arm length OA, and consequently the mechanical advantage, toaS skt to be the same for both patients. Table 1: Angular velocities for both patients Extension Flexion Average (degrees/s) (degrees/s) (degrees/s) Patient A 107 135 121 Patient B 107 92 99.5 Table 1 shows the lower leg extension and flexion angular veloc­ ities (co) for both patients. These velocities were calculated from the linear slopes in figures 5 and 6. It is evident from the table that, for both patients, the velocities in the two directions are not the same. In order to achieve the same velocity in both directions the damping capacity o f the shock absorber would have to change depending on the direction o f motion. This can be achieved but was not investi­ gated here since the exerciser was constructed merely to illustrate the concept. Nevertheless, it should be noted that even in the worst case presented here, i.e. patient A, the variation in velocity about the average is only 12%. For the rehabilitation o f many conditions this may be a perfectly acceptable tolerance. It is o f fundamental importance to note the subtle difference between this exerciser and current state-of-the-art isokinetic equip­ ment. Here, the patient's lower leg velocity is determined by the exerciser settings as well as the patient’s strength. Consequently, in assessing a patient, the therapist must first ascertain what settings will give a particular velocity range and then use this information to advance the patient through a spectrum o f velocities by lengthening or shortening the shock absorber/lever arm length OA. Naturally, the strenglh o f the patient will increase with repeated treatments and so too then will the velocity at a particular setting. This feature would have to be accounted for by the therapist. When a patient uses the exerciser with arbitrary settings, angular velocity will vary with angu­ lar displacement. However, it is up to the therapist to configure the exerciser so as to ensure isokinetic or nearly isokinetic motion. Depending on the skill o f the therapist the variation in velocity can be minimized and possibly eliminated. If both legs are exercised simultaneously and the mechanism settings arc the same, problems may arise with this exerciser, particu­ larly if one leg is significantly stronger than the other. Under these circumstances the stronger leg will tend to move faster than the weaker leg. This would then lead to coordination problems as the left and right legs would become increasingly out o f sync. It is important to note, however, that the left and right mechanisms are independent o f each other. Therefore, the mechanisms could be adjusted inde­ pendently with different settings so as to ensure the same average velocity for both legs. The results presented in the article show that, for a person with approximately equal strength legs, both legs can be exercised simultaneously, with both left and right mechanism settings the same, and the legs remain in sync. £ time (seconds) Fig 7: Torque characteristics for both patients in extension and flexion The angular displacement and velocity results described above were used in conjunction with the equation presented in the previous section to obtain the torque curves for both patients. The results are presented in figure 7 where positive torque denotes extension while negative torque denotes flexion. For extension, patient A produced a maximum torque o f 105 newton meters (Nm ), while patient B produced 97 Nm. Even though their angular velocities were identical the right hand side shock absorber damping coefficient was slightly larger than that on the left hand side and consequently patient A had to develop a larger torque to attain the same velocity. In flexion, the higher velocity o f patient A (see table 1) translated directly into a larger torque. This linear relationship can be clearly seen from the equation in the previous section. Here, patient A developed 103 Nm Physiotherapy, May 1992 Vol 48 no 2 Page 19 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. ) Boehringer Ingelheim nebulising solutions 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. ) New—Atrovent Inhalant Solution Unit Pose Vials • Added always to your standard I32 solution • Precise dose every time • Simple and convenient • Preservative-free Bisolvon® solution • Reduces bronchial and nasal secretion viscosity • Facilitates mucocilliary transport and expectoration Boehringer / ^ | \ Inhalation Ingelheim Therapy Creating a better clim ate for your patients S2 S2 S2 Atrovent 0,025% Inhalant Solution. Each ml contains 0,250 mg ipratropium bromide Reg. No. Q/10.2.1/117 Atrovent U.D.V. 0,5 mg/2 ml Inhalant Solution. Each 2 ml contains 0,5 mg ipratropium bromide (preservative free) Reg. No. X/10.2.1/322 Bisolvon Solution Each 5 ml contains bromhexine HC110 mg Ref. No. G642 (Act 101/1965) For further information about these and our other products, please contact; Boehringer Ingelheim (Pty) Ltd Reg. No. (69/08619/07) Private Bag X3032, Randburg, 2125 SPECTRUM113122 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. ) whereas patient B could only achieve 83 Nm. It has been shown in this section that the therapist must play a far greater role during rehabilitation than is the case when using other isokinetic equipment. This probably has additional merits of its own but is a vital ingredient to ensure the success of the exerciser. Indeed, it is a small price to pay when one considers that this exerciser will retail at a fraction o f the cost of imported equipment. The dire need for affordable equipment in this country cannot be over-stressed. CONCLUDING REMARKS An inexpensive exerciser has been described here which closely approximates the performance o f state-of-the-art isokinetic exerci­ sers. Unlike other exercisers o f this type, lower limb velocity cannot be set at the outset but the therapist can ensure a particular velocity range on the basis o f patient strength. It is also evident from the foregoing sections that the two most expensive items on the exerciser are commercially obtainable shock absorbers. It is thus obvious that this exerciser will be dramatically cheaper than any o f the isokinetic exercisers currently on the market. In fulfillment o f the BER U requirements it is evident that, pro­ vided the geometry o f the mechanism and the damping coefficient o f the shock absorber are known, the system is fully calibratable and is capable o f providing reproducible results over the entire range of movement. It has also been shown in the above sections that simple electronics and computer interfacing allow the simultaneous m eas­ urement of torque and angle in real time. One definite advantage of this exerciser over those like the Orthotron is that it allows enforce­ ment o f limited arc rotation which is important in many rehabilitation programs. ACKNOWLEDGEMENTS The author gratefully acknowledges Dr D F da Silva for his assist­ ance during the preliminary design phases and Drs EH Rosenberg and CM Lipman for providing financial support. Messrs T Rossini and TA Stacey are also acknowledged for setting up the data acquisi­ tion equipment and performing the experiments. REFERENCES 1. Thistle HG, Hislop HJ, Moffroid M eied. Isokinetic contraction: a new concept of resistive exercise. Archives o f Physical Medicine and Rehabilitation 1967;48:279-282. 2. Hislop HJ and Perrine JJ. The isokinetic concept of exercise. Physical Therapy 1967;47:114-117. 3. da Silva DF and Greenblatt D. The design of an isokinetic leg exerciser. 1986: Final year design report. University of the Witwatersrand. POST-CONGRESS SYMPOSIUM ON PAIN - A REPORT BACK b y ] C Beenhakker A symposium on pain which was held in Cambridge during Au­ gust, attracted speakers and participants world wide. Many thought- provoking and challenging papers were given by speakers who are specialists in their own field o f practice or research. Day one was devoted to the theories and mechanisms o f pain. When discussing the role o f nerves from muscles and joints, Profes­ sor P D Wall suggested that physiotherapy caused sensory stimula­ tion o f unmyelinated nerve fibres. This resulted in the release o f local chemicals together with stimulation o f the sympathetic system and o f motor nerves. Dr Newham, a physiologist, discussed the two types of muscle pain associated with exercise. The pain occurring during exercise is prob­ ably caused by trauma to muscles, severe metabolic depletion o f ATP and/or stretching of untrained muscles. Delayed onset of pain is mainly due to eccentric muscle contractions and occurs 12-20 hours after exercise. It is probably associated with muscle fatigue and impaired force generation. Contrary to what we believed, studies have shown that lactic acid is not responsible for ischemic pain. An interesting talk was given by Dr Williams, a neuro-surgeon, who outlined the chemical theory o f pain relief and compared the electro physiological to the biochemical approach. H e did not believe in surgery for most types o f pain relief and suggested that the best neuro-surgeon was one without arms! Several speakers discussed the function and value o f pain clinics which have proliferated all over the world. Mrs Allan from the Boston pain clinic discussed the role o f the physiotherapist in the inter disciplinary pain management team. As chronic pain leads to stress which causes further pain and dysfunction, Mrs Allan suggested that one o f the best ways o f dealing with this pain is by teaching stress coping management techniques. During day two presentations were made on trials carried out using electrotherapy modalities to relieve pain. Dr Mary Dyson discussed the w orking o f low level laser therapy and its e ffe c ts, which are mainly molecular vibration with som e electrical excitation. U se o f pulsed electromagnetic energy, interferential and pulsed short­ wave diathermy were also discussed. One afternoon was devoted to the theories of the psychological process in pain management. Mrs Klaber Moffett from the Nuffield Research Unit discussed how pain may be indirectly measured by behavioural responses to pain. For example by noting the increase or decrease in drug intake, alteration in measurement o f joint range or changes in functional activity, an indication o f the patient's pain level can be established. U se is also made o f pain diaries which are kept by the patient as well as the various pain scales and questionnaires which are mainly subjective. Dr Pither described the coping mechanisms regarding pain and how function is affected. He described a survey o f 89 patients who had chronic pain wherein it was found that these patients were over investigated and over treated, and very little advice and information had been given to the patients. He felt that many patients had iatrogenic distress and dysfunction and queried whether doctors were half the problem in chronic pain. The Input Programme which advocates a shift from curing pain to encouraging coping with existing pain was described by Ms Ridout. This program which is held in a group setting runs over five days a week for four weeks. Components o f the programme include fitness training, goal setting, withdrawal from drugs, functional and social activities, relaxation and cognitive skills. Patients are encouraged to make plans, challenge unhelpful beliefs and feelings, set goals and reinforce positive behaviour. During the final day papers were presented on the various m o­ dalities which may be used in the treatment o f pain. Dr Baldry defined myofascial pain and trigger points and discussed the use o f acupuncture. Mr Deadham, Editor o f the Journal o f Chinese m e­ dicine outlined the holistic approach o f eastern medicine while Ms Frampton described the use o f TNS. She discussed the differences between cortical pain such as causalgia and phantom pain and pe­ ripheral pain. She found that the most successful use o f TNS was using a width o f 50-360ms, 10-100 pulses per second at 0-50ma, which is given for eight hours a day over two to three weeks. An interesting discussion on manual therapy was given by Miss Thompson who postulated that pain was caused by lack of movement in joints, oedema, muscle spasm, joint entrapment or scar tissue. All o f these could be managed by massage, mobilisation, passive stretch­ ing, connective tissue massage, manipulation, hydrotherapy, acu­ puncture and PNF. Manual therapy is its broadest sense has been found to be a very useful tool if the correct technique is used at the right site. It is also important to be aware of the coping style o f the patient. The general impression gained from the symposium was that although it was important to relieve the physical aspect of chronic pain, this alone would not ensure a cure or even reduction in pain unless the cognitive and psychological aspects are considered concur­ rently. Bladsy 22 Fisioterapie, M ei 1992, dee! 48 no 2 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. )