An aquatic exercise program improved muscular strength, endurance, work and power in patients with multiple sclerosis. For the lower extremities, knee extensor peak torque significantly increased from pre- to mid-trial. Fatigue and work values improved significantly from pre- to post-trial. For the upper extremities, all force measurements significantly increased from pre- to post-trial. Power and total work values also improved significantly, though no significant change in fatigue was found. The results indicate aquatic exercise can induce positive changes to muscular functioning for individuals with multiple sclerosis.

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.
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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
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653

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
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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
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655

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
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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.
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657

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.
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