Effects of Isokinetic Training on the Rate of Movement
During Ambulation in Hemiparetic Patients
LYNNE GLASSER
The purpose of this study was to determine the effects of isokinetic training on
the rate of movement during ambulation in hemiparetic patients. Ten male and
10 female subjects, aged 40 to 75 years, participated in the study. The 20
hemiparetic subjects were assigned randomly to either a control group or an
experimental group. All of the subjects participated in a conventional therapeutic
exercise program and gait training. The experimental group also received isokinetic training on the Kinetron® exercise machine as part of their program. Functional ambulation profile tests were administered to each subject before and after
the five-week experimental period. All of the subjects showed improvement in
the rate of ambulation and in overall ambulation performance. The differences in
ambulation times and functional ambulation profile scores between the two
groups were shown to be insignificant.
Key Words: Exercise therapy, Gait, Hemiplegia.
Physical therapists use a variety of exercise theories and
procedures to facilitate or inhibit motor responses in the
extremities of hemiparetic patients. Three major modes of
training that physical therapists currently use are isometric,
isotonic, and isokinetic exercises.
In isometric exercise, relatively large resistance permits the
muscle to develop loading, but maximal tension is achieved
only at one point in the range of motion. The clinical value
of isometric exercise is limited because the demand it places
on the neuromuscular system does not always parallel an
individual's needs.1
During isotonic exercise, resistance to the body segment
remains constant throughout the entire ROM.1 The tension
demand placed on a muscle is maximal only during a small
portion of its ROM, causing the total work done to be less
than maximum capacity. The clinical value of isotonic exercise, therefore, is limited by its inability to impose maximal
tension and work demands on a muscle throughout its full
range of action.
Isokinetic exercise is different from the other modes. If
maximal muscular force is applied to the lever arm throughout the ROM and the speed of movement of the lever arm
remains constant, the muscle contraction is termed isokinetic.2 An isokinetic exercise machine provides resistance at
a fixed speed in direct proportion to the amount of muscle
force exerted by the subject. Resistance accommodates the
varying force at the skeletal lever, and the muscle is able to
maintain a state of maximal contraction through its full
ROM.
In Isotonic and isometric exercises, the speed of the body
segment is not specifically controlled. In isotonic exercise, the
speed of the body segment varies with the amount of muscular
Ms. Glasser is Assistant Professor, University of Medicine and Dentistry of
New Jersey-Kean College of New Jersey joint program in physical therapy, 100
Bergen St, Newark, NJ 07103 (USA). This study was conducted at Kessler
Institute for Rehabilitation, West Orange, NJ 07052, where she was employed
as a physical therapist. This article was adapted from her master's thesis,
completed at New York University, New York, NY 10003, September 1983.
This article was submitted March 5, 1984; was with the author for revision
28 weeks; and was accepted October 7, 1985.
Volume 66 / Number 5, May 1986
force exerted because the resistance is constant. Isometric
exercise may be considered as a technique of controlling the
speed at zero.1 During isokinetic exercise, the speed of the
body segment remains constant. Increased muscular force
produces increased resistance of the mechanical device. An
isokinetic exercise device provides a suitable mechanical
means of maintaining the maximal muscular force of a body
segment throughout a ROM without permitting acceleration.1
Initial studies conducted by Thistle et al,2 Smith and Melton,3 and Moffroid et al4 established that isokinetic exercise
increased performance levels more efficiently than other exercise modes. Experiments that followed these earlier studies
investigated specific training methods using isokinetic exercise
equipment.
Pipes and Wilmore5 compared isotonic and isokinetic
exercise training procedures and the differences between
low- and high-speed isokinetic exercise training. Their results
paralleled those obtained by Moffroid and Whipple.6 These
investigations showed that low-speed isokinetic exercise training produced greater increases in muscular force only at low
speeds, and high-speed isokinetic exercise produced increases
in muscular force at all speeds of muscle contraction at and
below the training speed.
Smith and Melton3 compared the Cybex®* and Nautilus®†
exercise machines for training healthy individuals. The results
of their study differed from those obtained by Pipes and
Wilmore5 and Moffroid and Whipple.6 Smith and Melton
showed that high-speed isokinetic exercise training produced
increases in muscular force only at high speeds, and lowspeed isokinetic exercise training produced increases in muscular force at both low and high speeds.3
The Cybex® was used for testing and training in most of
the studies that were conducted to assess the effects of isokinetic exercise. Another isokinetic exercise machine used by
* Cybex, Div of Lumex, Inc, 2100 Smithtown Ave, Ronkonkoma, NY
11779.
† Nautilus, Sports/Medical Industries, Inc, PO Box 1783, Dept PT, DeLand,
FL 32721.
673
physical therapists is the Kinetron®‡ Wilder and Sykes7 used
the Kinetron® as a training device for a hemiplegic patient.
The machine was set at a high speed of 10 and the patient
was required to maintain a pressure of 80 to 100 psi throughout the training program. After 27 sessions, the patient exhibited an increase in step and stride length of the involved
extremity, and gait deviations were minimized. The Kinetron® proved to be an effective training device for changing
the gait pattern of a spastic right hemiplegic patient.
Through these studies and others,8,9 isokinetic exercise has
been shown to increase performance levels more efficiently
than other exercise modes. Most of these investigations involved the use of healthy subjects; however, studies of the
effects of isokinetic exercise training on patients with a neuromuscular disorder are needed.
The purpose of my study was to determine the effects of
isokinetic exercise training on the rate of movement during
ambulation in hemiparetic patients. Evidence has shown that
high-speed isokinetic exercise training improves performance
at all speeds of muscular contraction at and below the training
speed. I hoped to demonstrate that high-speed isokinetic
exercise training would produce a quicker reaction of muscle
groups in the lower extremities, therefore, improving the rate
of ambulation in hemiparetic patients. I expected the experimental group to show significant decreases in ambulation
time and increases in the overall functional ambulation profile
scores when compared with the control group after completion of thefive-weektraining program using the Kinetron®.
METHOD
Subjects
Twenty hemiparetic patients between the ages of 40 and 75
years participated in the study. Each patient exhibited right
or left hemiparesis as a result of a cerebrovascular accident
(CVA) three to six months before the study. The cause of the
CVA in the majority of the subjects was thrombosis of the
middle cerebral artery.
The subjects were assigned randomly to either the control
or experimental group, with an equal number of right and
left hemiparetic patients in each group. The patients were
required to read and sign a consent form before participating
in the study. The experimental group consisted of one female
and four male left hemiparetic patients and three female and
two male right hemiparetic patients. The control group consisted of three female and two male left hemiparetic patients
and three female and two male right hemiparetic patients.
All of the subjects displayed upper and lower extremity
motor dysfunction. Some of the patients demonstrated more
sensory deficits than others, and some had mild forms of
expressive or receptive aphasia. According to Brunnstrom's
seven recovery stages,10 the control group subjects started with
the affected lower extremity in stages two and three, and the
experimental group subjects started in stages two, three, and
four.
Procedures
Three computerized functional ambulation profile (FAP)
tests were administered to each patient before and after the
‡ Kinetron, Lumex, Inc, 2100 Smithtown Ave, Ronkonkoma, NY 11779.
674
five-week experimental period. The FAP is a valid, reliable,
and objective method of assessing specific components of
ambulation and overall performance of locomotion.11 The
computerized system was designed and developed by J.
Tucker and by A. J. Nelson11 and currently is used at our
rehabilitation facility. The development of the computerized
FAP system has not been documented. The computer records
specific components of locomotion that include ambulation
time, speed, number of steps, cadence, step time, cycle time,
step length, stride length, and stride-extremity ratio. Each
patient was required to complete the three FAP tests during
one testing session. Thefirsttest was considered a preliminary
trial test and was not used in the final data analysis. The
average FAP scores of the last two tests were computed for all
of the patients.
The experimental and control groups were administered a
therapeutic exercise program that consisted of techniques
based on neurophysiological and developmental theories.
Eight physical therapists used the same specified therapeutic
exercise procedures to facilitate or inhibit motor responses in
the hemiparetic patients. They were given the specific instructions in the therapeutic exercise procedures to perform during
the sessions according to the methods described by Knott and
Voss,12 Bobath,13 Stockmeyer (Rood),14 and Brunnstrom.10
Each therapist treated at least one patient from each group,
and the therapists were responsible primarily for their assigned
patients throughout the study.
All of the patients were seen in the physical therapy department twice a day for one-hour treatment sessions for five
consecutive days each week. The therapeutic exercise program
and gait training were administered to the control group
during both treatment sessions. During the first week of the
training period, the experimental group received 1 hour and
50 minutes of therapeutic exercise and gait training with their
assigned therapist and then independently exercised for 10
minutes using the Kinetron®. An additional five minutes of
exercise using the Kinetron® was performed each week until
thefifthweek of the training program. During thefifthweek,
the patients in the experimental group exercised for 30 minutes using the Kinetron® and then received 1 hour and 30
minutes of therapeutic exercise and gait training. This particular progression of exercise using the Kinetron® was chosen
because of its potential effects on the patient's cardiovascular
system.
During the treatment sessions using the Kinetron®, each
patient in the experimental group sat on the machine in a
semi-sitting position with one lower extremity stabilized at 30
degrees of hip flexion and 20 degrees of knee flexion. The
patients performed 25 repetitions of bilateral lower extremity
exercise, rested one minute, and then repeated the procedure
for the total time interval selected for that particular week of
the training program. One repetition on the Kinetron® was
considered to be one heel strike to heel strike on the same
lower extremity. The patients were required to maintain a
pressure of 50 to 100 psi on the gauges set in front of them
while they performed the exercises.
The Kinetron® was set at one speed for each subject
throughout thefive-weekperiod. The speed was determined
for each subject using the following procedure. One lower
extremity was stabilized at 30 degrees of hip flexion and 20
degrees of knee flexion. The patient was instructed to complete one repetition on the Kinetron®. The time that elapsed
PHYSICAL THERAPY
RESEARCH
for the patient to perform one repetition was recorded using
a stopwatch to approximate the cycle time for that individual.
The trial cycle times varied among the subjects; therefore, the
speed settings on the Kinetron® ranged from 6 to 10 during
the training program. The speed of the machine then was set
for each daily treatment session according to the speed setting
that was established during the trial.
TABLE 1
Two-Way Analysis of Variance Factorial Design with Repeated
Measures on One Factor (Time) for Functional Ambulation
Profile Scores
Source
Between subjects
Group
Error
Within subjects
Time
Group x time
Error
Data Analysis
The differences in the overall FAP scores between the two
groups were compared using the two-way analysis of variance
(ANOVA) factorial design with repeated measures on one
factor.15 Pretest values were compared using an unpaired t
test. The same procedure was used to compare ambulation
times between the groups. The analyses also included the
comparison of differences within the groups for time and
interaction effects.
a
DISCUSSION
The patients in this study progressed through Brunnstrom's
recovery stages10 at different rates. All of the patients improved in lower extremity motor function. The patients began
in categories two, three, and four and progressed to the next
stage of recovery after the five-week program. No difference
was observed in the changes between the experimental and
control groups after the training period.
An observation that was made during the experiment related to the motivation that was demonstrated by the patients
using the isokinetic exercise device. The patients in the experimental group began the Kinetron® training program with
enthusiasm. As the patients progressed through the five-week
program, a decrease in motivation and enthusiasm was evident. Some of these patients seemed to prefer the individual
Volume 66 / Number 5, May 1986
19
1
18
20
1
1
18
SS
6042.57
596.76
5445.81
3056.13
2066.41
35.16
954.56
MS
F
596.76
302.54
1.97
2066.41
35.16
53.03
38.97a
0.66
p <.0001.
TABLE 2
Two-Way Analysis of Variance Factorial Design with Repeated
Measures on One Factor (Time) for Ambulation Time
RESULTS
All of the subjects showed improvement in overall ambulation performance as measured by FAP scores and the rate
of ambulation. Table 1 shows the results of the ANOVA for
FAP scores. The differences in the FAP scores between the
experimental and control groups were found to be insignificant. The differences in the FAP scores over time within each
group of patients showed significant results (p < .0001). The
effect within each group was the change in performance
observed over time and was independent of the type of
treatment that the patients received.
The two-way ANOVA in Table 2 shows no significant
difference for ambulation time between the experimental and
control groups. The differences in ambulation time within
each group of patients were significant (p < .0001).
Table 3 illustrates the means and standard deviations for
pretest and posttest values of FAP scores and ambulation
times of both groups. The mean of the FAP scores was lower
and the mean of ambulation times was higher in the control
group when compared with the experimental group before
treatment was administered. The difference between mean
pretest values of the two groups was not significant at the .05
level for ambulation performance and ambulation time. Both
groups showed a similar mean improvement in overall ambulation performance and similar mean decreases in ambulation time.
df
a
Source
df
SS
Between subjects
Group
Error
Within subjects
Time
Group x time
Error
19
1
18
20
1
1
18
3050.90
161.48
2889.42
1638.85
1015.56
4.88
618.41
MS
F
161.48
160.52
1.01
1015.56
4.88
34.36
29.56a
0.14
p <.0001.
TABLE 3
Means and Standard Deviations for Pretest and Posttest Values
of Functional Ambulation Profile Score and Ambulation Time
Group
Time
FAP Score
Ambulation
Time
s
Control
Experimental
Pretest
Posttest
Pretest
Posttest
51.55
67.80
61.15
73.65
9.08
14.26
11.43
17.16
s
24.07
13.30
19.35
9.98
16.41
7.82
7.08
3.03
attention and manual exercises provided by their assigned
therapist. The results obtained in the experiment may have
been affected by this psychological factor.
Studies that have been conducted using isokinetic exercise
equipment have shown that isokinetic exercise increased performance levels more efficiently than other exercise modes.
Thistle and his associates compared the results of isokinetic
exercise with the results of progressive resistive and isometric
exercises using healthy subjects.2 The group that received
isokinetic exercise using the Cybex® scored higher than the
other groups in total work output and peak force generated.
In comparison with past studies, my investigation did not
show a difference in results between isokinetic exercise training and other exercise modes. Each control group patient
showed an improvement in the rate of ambulation after
completing the therapeutic exercise program. The experimental and control groups showed no significant differences in
ambulation performance after the five-week program.
Evidence also exists that isokinetic exercise training at
higher speeds increased performance more efficiently than
isokinetic exercise training at slower speeds. The study con675
ducted by Barnes showed that muscular deficiencies occurring
at specific contractile speeds might be identified and corrected
by having the patient exercise isokinetically at the speeds at
which the differences occurred.8 To improve performance of
patients with a neuromuscular disorder in my investigation, I
set the isokinetic exercise device at speeds of 6 through 10,
demanding muscular contractions at higher speeds where
muscular deficiencies existed. Each patient in the experimental group showed significant improvement in the rate of
ambulation after high-speed isokinetic exercise training.
These results confirm the findings obtained by Barnes.8
Minimal research has been undertaken using the Kinetron®
as a training device. Many of the past isokinetic exercise
studies were conducted on healthy subjects using the Cybex®
for testing and training. Further study is recommended using
the Kinetron® in different training regimens for patients with
various types of neuromuscular disorders. Future research
also may compare the performance levels of hemiparetic
patients in various stages of recovery. Isokinetic exercise
training may prove to be more beneficial in the later stages of
recovery in hemiparetic patients. The performance levels of
left and right hemiparetic patients also may be compared.
CONCLUSION
The 20 hemiparetic patients who participated in the study
showed an overall improvement in ambulation performance.
The experimental and control groups exhibited significant
improvement in ambulation time. The experimental group
began the therapeutic exercise program with faster ambulation
times than the control group, but both groups showed equal
progress after thefive-weektraining period. The difference in
ambulation time between the two groups was shown to be
insignificant. No significant difference was found in the rate
of ambulation between the group that participated in an
676
isokinetic exercise training program and the group that participated in a conventional therapeutic exercise program.
Acknowledgments. I thank Dr. Marilyn Moffat for her
guidance and support throughout the preparation of this
study. I also acknowledge Mr. Marty Feurman, the biostatistician at the University of Medicine and Dentistry of New
Jersey who prepared the statistical analysis. Finally, I sincerely
thank the physical therapists at Kessler Institute for Rehabilitation for their cooperation and participation in this study.
REFERENCES
1. Hislop HJ, Perrine JJ: The isokinetic concept of exercise. Phys Ther
47:114-117,1967
2. Thistle HG, Hislop HJ, Moffroid MT, et al: Isokinetic contraction: A new
concept of resistive exercise. Arch Phys Med Rehabil 48:279-282,1967
3. Smith MJ, Melton P: Isokinetic versus isotonic variable-resistance training.
Am J Sports Med 9:275-279,1981
4. Moffroid MT, Whipple RH, Hofkosh J, et al: A study of isokinetic exercise.
Phys Ther 49:735-747,1969
5. Pipes TV, Wilmore JH: Isokinetic versus isotonic strength training in adult
men. Med Sci Sports 7:262-274,1975
6. Moffroid MT, Whipple RH: Specificity of speed of exercise. Phys Ther
50:1692-1700,1970
7. Wilder PA, Sykes J: Using an isokinetic exercise machine to improve the
gait pattern in a hemiplegic patient: A case report. Phys Ther 62:12911295,1982
8. Barnes WS: The relationship of motor-unit activation to isokinetic muscular
contraction at different contractile velocities. Phys Ther 60:1152-1158,
1980
9. Perrine JJ, Edgerton RV: Muscle force-velocity and power-velocity relationships under isokinetic loading. Med Sci Sports 10:159-166,1978
10. Brunnstrom S: Movement Therapy in Hemiplegia: A Neurophysidogical
Approach. New York, NY, Harper & Row, Publishers Inc, 1970
11. Nelson AJ: Functional ambulation profile. Phys Ther 54:1059-1065,1974
12. Knott M, Voss DE: Proprioceptive Neuromuscular Facilitation: Patterns
and Techniques, ed 2. Philadelphia, PA, J B Lippincott Co, 1968
13. Bobath B: Adult Hemiplegia: Evaluation and Treatment, ed 2. London,
England, William Heinemann Medical Books Ltd, 1978
14. Stockmeyer SA: An interpretation of the approach of Rood to the treatment
of neuromuscular dysfunction. Am J Phys Med 46:900-961,1967
15. Winer BJ: Statistical Principles in Experimental Design. New York, NY,
McGraw-Hill Inc, 1971, p 526
PHYSICAL THERAPY