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  1. 1. Effects of an Aquatic Fitness Program on the Muscular Strength and Endurance of Patients with Multiple Sclerosis Gale M Gehlsen, Susan A Grigsby and Donald M Winant PHYS THER. 1984; 64:653-657. The online version of this article, along with updated information and services, can be found online at: http://ptjournal.apta.org/content/64/5/653 Collections This article, along with others on similar topics, appears in the following collection(s): Multiple Sclerosis Therapeutic Exercise e-Letters To submit an e-Letter on this article, click here or click on "Submit a response" in the right-hand menu under "Responses" in the online version of this article. E-mail alerts Sign up here to receive free e-mail alerts Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013
  2. 2. Effects of an Aquatic Fitness Program on the Muscular Strength and Endurance of Patients with Multiple Sclerosis GALE M. GEHLSEN, SUSAN A. GRIGSBY, and DONALD M. WINANT This study quantified the effects of an aquatic exercise program on muscular strength, endurance, work, and power of patients with multiple sclerosis. Ten individuals with a mean age of 40 years participated in a 10-week aquatic exercise program. Two types of isokinetic dynamometers were used to assess the muscular variables studied. A Cybex® II dynamometer was used to measure peak torque, work, and fatigue in the knee flexor and extensor muscles and a biokinetic swim bench was used to measure muscular force, work, fatigue, and power in the upper extremities. Five velocity settings were selected for each of three testing trials (pretrial, midtrial, and posttrial). For the lower extremities, analysis of variance indicated a significant improvement of peak torque for knee extensor muscles from the pretrial to midtrial (p < .05). Peak torque values from pretrial to midtrial for knee flexors and from midtrial to posttrial for both the knee extensor and flexor muscles indicated a nonsignificant difference at each velocity studied. Fatigue and work values in the lower extremities improved significantly between the pretrial and posttrial (p < .05). For the upper extremities, an analysis of variance indicated a significant increase in all force measurements from pretrial to posttrial (p < .05). Power and total work values also improved significantly (p < .05). No significant difference in fatigue measurements for the upper extremities was found. The results of this investigation indicated that an aquatic exercise program may induce positive changes in muscular strength, fatigue, work, and power in patients with multiple sclerosis. Key Words: Exercise therapy, Multiple sclerosis, Physical therapy, Water. Multiple sclerosis (MS) is a degenerative neurological disorder characterized by the demyelinization of CNS pathways that may, in part, be responsible for the neuromuscular dysfunction found in persons with the disease. The primary focus of research in this area has been on determining the etiology of the disease and development of a cure rather than on trying to improve the general fitness of the patient. Because the etiological origin of MS has yet to be determined, treatment has been limited to the control of symptomatic complications, such as muscular fatigue, weakness, contracture, and spasticity, through physical therapy and the use of drugs.1-3 Exercise programs directed toward treating certain specific deficits have been viewed by some as having the most to offer patients with MS.4 Traditionally, such techniques as active and passive range of motion, coordination exercises, and various facilitation techniques to induce voluntary motor activity or inhibit unwanted motor patterns have been used Dr. Gehlsen is Professor of Physical Education and Director of the Biomechanics Laboratory, Ball State University, Muncie, IN 47306 (USA). Ms. Grigsby is Assistant Professor, Physical Therapy Program, Department of Physiology and Health Science, Ball State University, Muncie, IN. Mr. Winant was a graduate student in the Department of Men's Physical Education, Ball State University, when this study was conducted. He is currently a Research Assistant, Department of Rehabilitative Medicine, University Hospital, University of Washington, Seattle, WA 98105. This article was submitted March 14, 1983; was with the authors for revision 18 weeks; and was accepted December 20, 1983. to help alleviate or modify neuromuscular complications, such as ataxia, spasticity, contracture, and disuse atrophy of the skeletal muscles.5 A more recent trend has favored the use of dynamic exercise (calisthenics, cycling, and swimming) for sustaining the physical conditioning response and preventing neuromuscular complications associated with physical inactivity.5,6 Russell has implied that dynamic exercise creates a hyperaemic response in the body that results in opening up circulation to the ischemic regions of the spinal cord and brain.6 He observed that a rest-exercise program for patients with MS arrested the pathogenic process by preventing the fulminating or malignant type or both from developing. Certain physical activities, such as jogging, may be inappropriate for patients with MS because of exposure to harsh environmental conditions and the requirement for stamina and balance beyond the patients' capacities. The buoyant nature of water and the ability to control water temperature effectively, however, are characteristics that have made a positive therapeutic response in patients with neuromuscular disease possible.7 No empirical evidence is available on the benefits of an aquatic exercise program for the patient with MS. The physical therapist, therefore, is unable to make any recommendation (positive or negative) concerning aquatic exercise programs for patients with MS. The purpose of this study was to determine the effects of an aquatic exercise program on the Volume 64 / Number 5, May 1984 Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013 653
  3. 3. TABLE 1 Demographic Data of Subjects with Multiple Sclerosis Weight (kg) Subject No. Age (yr) Sex Height (M) Pretrial 1 2 3 4 5 6 7 8 9 10 30 54 61 23 51 37 36 35 37 38 Woman Woman Woman Woman Woman Woman Man Man Man Man 1.80 1.68 1.59 1.68 1.68 1.62 1.87 1.76 1.82 1.83 59.0 57.2 59.1 62.2 79.8 54.0 77.6 69.3 74.0 78.0 Midtrial Posttrial 58.0 59.8 55.9 56.0 57.8 60.0 59.7 60.8 79.4 79.3 53.8 54.0 76.2 75.0 71.5 70.1 73.4 73.7 73.4 74.8 upper and lower extremity muscular force, torque, fatigue, work, and power in patients with MS. The study attempted to quantify the effects of the aquatic program on muscular strength and endurance of individuals with MS to determine whether this type of exercise program could be effectively used by the clinician to improve overall patient conditioning. METHOD Subjects A total of 13 subjects comprised the initial experimental group, but 3 subjects dropped out of the study before the fifth week of testing. We collected data on 10 subjects with MS (six women and four men) with a mean age of 40.2 years. The subjects were recruited from the local Multiple Sclerosis Association Chapter. We based eligibility on clinical assessment of disease status by attending physicians. Selection criteria required that all subjects be ambulatory and the disease be in a remissive state. We obtained informed consent as a prerequisite for participating in the laboratory tests and exercise program. Table 1 lists demographic data. Experimental Design We scheduled three testing trials of the upper and lower extremities' muscular torque, force, fatigue, work, and power for each of the 10 subjects on two types of isokinetic dynamometers. The pretrial tests were administered the week before the start of a 10-week aquatic exercise program; the midtrial tests were conducted during the fifth week of the aquatic exercise program; and the posttrial tests were administered during the week following the completion of the aquatic exercise program. Equipment We used a Cybex®* II isokinetic dynamometer to measure knee joint flexor and extensor muscle peak torque at angular velocities of 60, 120, 180, 240, and 300°/sec. A digital work integrator (a component of the Cybex® II) was used to determine total work. A biokinetic swim bench† measured peak force, total work, and maximal power at varying upper extremity velocities. * Cybex, Div of Lumex, 2100 Smithtown Ave, Ronkonkoma, NY 11779. † Isokinetic. Inc, PO Box 6397, Albany, CA 94706. The apparatus was a semiaccommodating resistance device that could be preset at a regulated speed to provide a constant amount of velocity in proportion to the force applied by the user. The speed setting(s) were S-0 (0.9 m/sec), S-2 (1.24 m/ sec), S-4 (1.7 m/sec), S-6 (2.2 m/sec), and S-8 (2.72 m/sec). The swim bench was designed with a padded incline for a prone position and with pull paddles for the hands of the subjects. Each paddle connected to an attached isokinetic resistance device by one rope that ran over a pulley and around the geared spool inside. A governor built onto the spool regulated the rate at which each rope released from the spool. The force generated during each arm pull was determined from a physiograph chart recorder; muscular work was measured with the digital work integrator (a component of the swim bench); time was measured by the length of the force curve; and muscular power was calculated by dividing work by the time of the pull. Test Protocol Lower extremities. Before each testing session, the dynamometer, chart recorder, angle channel, and digital work integrator were calibrated. The subjects underwent a fiveminute warm-up period consisting of two contractions at the designated angular velocities. We minimized extraneous body movement by restraining each subject with shoulder harnesses, a hip belt, a midthigh restraint strap, and an ankle strap. The level-arm length and the number of back support pads remained constant for each subject; we positioned the midpoint of the lever-arm crank next to the lateral femoral condyle of the knee joint. The testing protocol required that each subject continue at each preset angular velocity until peak torque decline was observed. We conducted retests at specified angular velocities to verify peak torque values. After dynamic torque measurements were obtained, the isometric (0°/sec) torque of the knee extensor and flexor muscles was taken at a leg angle of 45 degrees. We gave the subjects five minutes of rest before total work data were obtained from a test of 50 (extension) contractions at the preset speed of 180°/ sec. Muscular fatigue values were calculated from the total work data. We considered fatigue values to be the percentage of peak torque decline (the percentage of difference between the first and final peak torque values) as described by Thorstensson.8 Upper extremities. We familiarized all subjects with the use of the biokinetic swim bench and allowed them a warm-up of two practice pulls at each speed setting. Peak force measurements were obtained from the best of three trials at speed settings S-0, S-2, S-4, S-6, and S-8. After a five-minute rest period, each subject performed a 45-second muscular total work and fatigue test. The total work and fatigue test was performed at the high tension speed setting of S-0 (0.9 m/ sec). The digital work integrator recorded the total work produced during the test. We measured fatigue as the percentage of decline of peak force from the average of the first three and last three arm pulls. As stated previously, power was calculated from the results of the work tests and the time of the pull. We instructed each subject to give a maximal effort on every muscular contraction. Verbal encouragement was given during each test. 654 Physical Therapy Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013
  4. 4. RESEARCH TABLE 2 Cybex® II Dynamometer Results: Peak Torque Values of Knee Extensor" and Flexor Muscles at Predetermined Angular Velocities Difference (%) Pretrial (Nm) Midtrial (Nm) Posttrial (Nm) s s s Pretrial to Midtrial Midtrial to Posttrial Pretrial to Posttrial 18.9 32.4 27.5 32.7 22.4 26.4 19.1 17.8 16.7 15.3 14.8 14.2 31.8 7.6 28.2 24.0 25.5 26.3 36.7 39.8 53.8 51.2 81.8 90.5 1.9 -1.4 -3.2 -9.1 -3.3 -5.6 -3.3 -13.5 -8.9 -20.3 -21.7 -22.5 33.9 6.0 24.3 12.7 21.6 19.4 32.7 20.1 40.3 20.1 42.5 47.8 Angular Velocity 0°/sec Flexion Extension 60°/sec Flexion Extension 120°/sec Flexion Extension 180°/sec Flexion Extension 240°/sec Flexion Extension 300°/sec Flexion Extension a 32.4 85.6 37.0 70.5 28.7 45.4 19.9 30.9 16.1 22.8 13.4 14.2 19.9 25.9 30.1 34.2 26.9 28.2 22.1 23.0 18.2 19.2 16.4 15.3 42.6 92.1 47.5 87.5 36.1 57.4 27.3 42.9 24.8 34.4 24.4 27.1 43.4 90.8 46.0 79.5 34.9 54.2 26.4 37.1 22.6 27.4 19.1 21.0 16.9 32.1 31.5 40.8 26.6 32.4 20.6 25.5 20.5 23.2 21.4 20.5 All extension pretrial to midtrial values except 0°/sec significant (p < .05). Aquatic Exercise Program Data Analysis All subjects participated in a 10-week exercise program consisting of freestyle swimming and shallow water calisthenics, as outlined by the President's Council on Physical Fitness and Sports7 and Getchell and Anderson.9 The program site was a 25-m by 15-m instructional facility. We regulated water temperature within a range of 25° to 27.5°C (77°-81.5°F). Exercise prescription was based on the guidelines recommended by the American College of Sports Medicine.10 The frequency of exercise was set at 3 one-hour exercise sessions each week; training intensity was established at 60 to 75 percent of the subject's estimated maximal heart rate. We based progression of exercise intensity and duration on submaximal heart rate; subjective feelings of fatigue; periodic clinical assessment by attending physicians; and monitoring of resting, recovery, and maximal training heart-rate responses. We used a two-way analysis of variance (SPSS computer program) to test for significance of effects for the following variables: muscular torque, force, work, and power at selected movement speeds. The percentage of change was computed for the torque, work, and fatigue variables by the following formula: (1) RESULTS Torque and Force Table 2 presents the mean peak torque data from the dynamometer testing for knee flexion and extension. Peak torque measurements for the knee extensor muscles indicated significant improvement (p < .05) from pretrial to midtrial TABLE 3 Biokinetic Swim-Bench Results: Mean-Force, Work, and Power Values at Predetermined Speed Settings for Upper Extremities Variable Pretrial Midtrial S-0 Posttrial Pretrial Midtrial S-2 Posttrial Pretrial Midtrial S-4 Posttrial Pretrial Midtrial S-6 Posttrial Pretrial Midtrial S-8 Posttrial 129.2 57.9 148.5 57.6 189.5 65.3 80.3 61.3 99.5 58.1 128.2 59.2 53.8 46.8 69.9 53.7 87.9 47.1 32.3 32.5 42.9 36.1 58.8 46.7 16.0 24.0 24.9 27.0 29.6 32.0 89.3 43.4 105.6 38.8 126.3 46.3 42.4 37.0 56.6 35.6 66.4 37.2 25.0 24.0 32.6 28.5 39.2 26.4 15.2 16.3 19.6 18.3 21.7 20.0 4.3 8.6 9.8 12.0 11.9 12.7 57.8 43.0 77.9 49.6 92.0 47.5 59.6 55.8 80.9 57.0 95.5 60.3 57.2 54.1 76.8 64.6 97.0 58.5 61.5 55.9 75.6 67.1 81.9 61.3 21.7 43.2 52.6 56.8 66.2 66.1 Forcea (N) s Workb (Nm) s Powerc (Nm/sec) s a Significant (p < .05) between trials and speeds. Significant (p < .05) for all trials except S-6. c Significant (p < .05) pretrial to posttrial except S-6. b Volume 64 / Number 5, May 1984 Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013 655
  5. 5. for all designated angular velocities except for 0%ec. We found no statistical difference in mean peak torque values for knee flexor muscles from pretrial to midtrial nor any significant differences for each of the respective angular velocities. All flexor and extensor peak torque values except the knee flexors at 0°/sec decreased between the midtrial and posttrial. Peak torque from pretrial to posttrial and midtrial to posttrial for both the knee extensor and flexor musculature indicated nonsignificant difference for all of the angular velocities. Table 2 also gives percentage of change between the peak torque values from the pretrial to midtrial, midtrial to posttrial, and pretrial to posttrial for the knee flexor and extensor muscles. creased. Table 3 presents mean data for work. The total work as measured during the 45-second, swim-bench test increased significantly (p < .05) from pretrial to posttrial. The percentage of increase from pretrial to midtrial was 39 percent, and the increase in total work from the pretrial to posttrial was 82 percent (Tab. 4). As for the swim-bench fatigue values, no statistically significant difference could be found between trials. The data showed that the fatigue value increased (14%) from the prefatigue to postfatigue test trial. Power At the .05 level of significance, mean power of the upper extremities improved (pretrial to posttrial) at all the speed settings other than S-6. Peak power was recorded at S-4 posttrial (97.0 Nm/sec); at S-8 pretrial (21.7 Nm/sec), power output was lower than at all other speed settings. Mean power values can be found in Table 3. Table 3 presents the mean force values for the upper extremities at the various speed settings for the swim bench. At all of the speed settings, two-way analysis of variance revealed a significant difference (p < .05) in peak force values for the three testing periods and a significant difference (p < .05) between the speeds of movement. Mean force output was greatest at the high tension speed settings of S-0 and S-2; the force output progressively declined at the lower tension speed setting of S-4, S-6, and S-8, respectively. The percentage of increase in mean force values from pretrial to posttrial ranged from 46.7 to 85.0 percent. DISCUSSION The results of this investigation indicated that individuals with MS who participated in a program of aquatic exercise were able to overcome some of the neuromuscular deficits characteristic of the disease process. Factors that may have influenced the outcome of the muscular force, torque, work, and fatigue measurements included 1) the specificity of training principle, 2) neuropathological influences of MS on skeletal muscle, 3) physical inactivity, and 4) diurnal physiological alterations. Isokinetic dynamometry data revealed that maximal peak torque for the knee extensor muscles was recorded at the isometric setting (0°/sec). No statistical differences were obtained, however, for the three trial sessions at the isometric setting. Similar results were obtained by Larsson, who strength-trained previously sedentary adult men.11 Larsson found that although maximum peak torque was produced at the isometric setting, no statistical significance could be found when comparing the results of pretrial, midtrial, and posttrial. The insignificant results for isometric peak torque may indi- Muscular Work and Fatigue Table 4 outlines group means for total muscular work and fatigue (percent decrement in peak torque) for the Cybex®. The total work of the knee extensor muscles increased by 192 percent from pretrial to midtrial and 330 percent from the pretrial to posttrial. The total work improvement was statistically significant (p < .05). The lower extremities' fatigue values (percentage of decline in peak torque) showed a statistically significant (p < .05) decrease. The absolute differences in the fatigue values were 12.84 and 14.14 percent for the pretrial to midtrial and pretrial to posttrial, respectively. As determined by significance testing (p < .05), work for the upper extremities improved at all of the speed settings, with the exception of S-6. As was characteristic of force, work progressively decreased as the speed setting (velocity) inTABLE 4 Total Work Production" and Fatigueb for Upper and Lower Extremities Difference (%) Pretrial Period Midtrial Period Posttrial Period s s s Pretrial to Midtrial Midtrial to Posttrial Pretrial to Posttrial 330.2 -25.6 Test Equipment Cybex® I I total work (Nm) fatigue (% decline in force) Swim bench total work (Nm) fatigue (% decline in force) 1078.90 55.15 817.80 11.02 3151.70 42.31 1780.50 12.57 4641.40 41.01 1084.40 14.97 192.1 -23.3 47.3 -3.1 1093.40 29.78 658.60 15.26 1522.00 31.57 294.20 14.09 1990.80 33.95 1091.70 18.93 39.2 6.0 30.8 7.5 82.1c 14.0 a Significant (p < .05) between trials. Significant (p < .05) between trials. c Significant (p < .05) pretrial to posttrial. b 656 Physical Therapy Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013
  6. 6. RESEARCH cate the lack of training specificity between dynamic and static exercise. Investigations by Osternig and associates12 and Wolf13 have shown that isometric peak torque demonstrated a low correlation with dynamic peak torque, and the patterns of motor unit recruitment varied depending on whether the nature of muscular contraction was static or dynamic. Although dynamic peak torque values for the knee extensors showed a significant increase from pretrial to midtrial dynamometer measurements in our study, the results failed to indicate any improvement in dynamic peak torque for the knee flexor muscles. The lack of muscular torque gains for the knee flexors may be related to the general muscular weakness and contracture problems faced by patients with MS.5, 14 The extent of pyramidal pathway involvement may have also compromised the ability of the knee flexor musculature to improve with exercise. Birch et al stated that training cannot influence irrevocable CNS damage.15 The general trend for the swim-bench data indicated a significant improvement in the components of strength (force, work, and power) for all three experimental trials. The reason why the strength components gains were most evident for the upper extremities and not for the lower extremities may be related to discrepancies in testing protocols for the dynamometer and swim bench. Specificity of training may have also been a key factor influencing the outcome of the force and torque measurements. Costill and associates have stated that devices that measure strength must duplicate the actual biomechanical patterns of a particular skill.16 Swim-bench measurements revealed that at the high tension settings of S-0 and S-2 and medium tension setting of S4, force, work, and power showed significant gains; however, at the low tension settings of S-6 and S-8, significant improvements in force, work, and power were not quite so dramatic. The somewhat variable findings at the faster velocities may be related to the duration and intensity of the aerobicallyoriented exercise. Elliott stated that muscles that are trained at fast velocities become capable of improving strength at both fast and slow speeds; however, if training takes place under conditions of high resistance or slow velocities or both, quickness and power are sacrificed.17 The inability to produce peak torque at the faster velocities may also be because of the demyelinating-denervating process so characteristic of MS. Edstrom hypothesized that in upper motor neuron lesions (with paresis and spasticity), there may be selective disuse of high threshold motor units, which innervate fast twitch (FT) fibers, and overuse of low threshold motor units/which innervate slow twitch (ST) musclefibers.18This situation would then result in atrophy of the high threshold motor units and FTfibersand in hypertrophy of the low threshold motor units and ST fibers. The predominance of ST muscle fibers in upper motor neuron lesions may indicate that in patients with MS, muscle function may be compromised. Perhaps, the most universal symptom encountered by persons with MS is fatigue. Typically, patients with MS follow a diurnal cycle in which they awaken in the morning fairly rested, progressively fatigue throughout the day, and recover in the evening.19 The results of this investigation indicated that muscular work and muscular fatigability can be dramatically improved in patients with MS. The results indicated an 82 percent increase in the total work measurement for the upper extremities and a 330 percent increase in the total work measurement for the lower extremities. The percent decline in peak torque (fatigue measure) for the lower extremities decreased from 55 percent to 41 percent; a significant improvement in the ability of the muscles to maintain peak torque. CONCLUSION In light of the mentioned factors that may have influenced the results of this investigation, we concluded that an aquatic exercise program is not harmful to the muscular strength and endurance of patients with MS. The results, although mixed, did indicate that some positive changes in muscular strength (force and torque), fatigue, work, and power can be expected from an aquatic exercise program. The small sample group and mixed results of this study would indicate the need for further research in this particular area. REFERENCES 1. Cook AW, Weinstein SP: Chronic dorsal column stimulation in multiple sclerosis: Preliminary report. NY State J Med 73:2868-2872, 1973 2. Cook AW: Electrical stimulation in multiple sclerosis. Hosp Pract 11:5158,1976 3. IIIis LS, Oygar AW, Sedgwick EM, et al: Dorsal-column stimulation in rehabilitation of patients with multiple sclerosis. Lancet 1(7974):13831386,1976 4. Gordon EE, Carlson EE: Changing attitude toward multiple sclerosis. JAMA 147:720-723,1951 5. Cailliet R: Exercise in multiple sclerosis. In Basmajian JV (ed): Therapeutic Exercise, ed 3. Baltimore, MD, Williams & Wilkins, 1980, pp 375-388 6. Russell RW: Disseminated sclerosis: Rest-exercise therapy. In Russell RW (ed): Multiple Sclerosis: Control of the Disease. New York, NY, Pergamon Press Inc, 1976, pp 67-76 7. President's Council on Physical Fitness and Sports: Aqua Dynamics: Physical Conditioning Through Water Exercises. Washington, DC, United States Government Printing Office, 1977, 0-250-914, pp 33 8. Thorstensson A: Muscle strength, fiber types and enzyme activities in man. Acta Physiol Scand [Suppl] 443:7-45, 1976 9. Getchell B, Anderson W: Being Fit: A Personal Guide. New York, NY, John Wiley & Sons Inc, 1982, p 312 10. American College of Sports Medicine: Guidelines for Graded Exercise Testing and Exercise Prescription, ed 2. Philadelphia, PA, Lea & Febiger, 1980, p 151 11. Larsson L: Physical training effects on muscle morphology in sedentary males at different ages. Med Sci Sports Exerc, 14:203-206, 1982 12. Osternig LR, Bates BT, James SL: Isokinetic and isometric torque force relationships. Arch Phys Med Rehabil 58:254-257, 1977 13. Wolf SL: The morphological and functional basis of therapeutic exercise. In Basmajian JV (ed): Therapeutic Exercise. Baltimore, MD, Williams & Wilkins, 1980, p 63 14. Rusk HA: Rehabilitation Medicine. St. Louis, MO, CV Mosby Co, 1977, p 460 15. Birch HG, Proctor F, Bortner M, et al: Perception in hemiplegia: I. Judgment of vertical and horizontal by hemiplegic patients. Arch Phys Med Rehabil 41:19-27,1960 16. Costill DL, Sharp RL, Troup J: Muscle strength: Contributions to sprint swimming. In Flavell ER (ed): Biokinetic Strength Training. Albany, CA, Isokinetics, Inc, 1981, p 216 17. Elliott J: Assessing muscle strength isokinetically. JAMA 240:2408-2410, 1978 18. Edstrom L: Selective changes in the size of red and white muscle fibers in upper motor lesions and parkinsonism. J Neurol Sci 11:537-550, 1970 19. O'Sullivan SB, Cullen KE, Schmitz TJ: Physical Rehabilitation: Evaluation and Treatment Procedures. Philadelphia, PA, F.A. Davis Co, 1981, pp 249-257 Volume 64 / Number 5, May 1984 Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013 657
  7. 7. Effects of an Aquatic Fitness Program on the Muscular Strength and Endurance of Patients with Multiple Sclerosis Gale M Gehlsen, Susan A Grigsby and Donald M Winant PHYS THER. 1984; 64:653-657. Cited by This article has been cited by 12 HighWire-hosted articles: http://ptjournal.apta.org/content/64/5/653#otherarticles Subscription Information http://ptjournal.apta.org/subscriptions/ Permissions and Reprints http://ptjournal.apta.org/site/misc/terms.xhtml Information for Authors http://ptjournal.apta.org/site/misc/ifora.xhtml Downloaded from http://ptjournal.apta.org/ by guest on February 4, 2013