CASE REPORT
Effects of Prosthetic Gait Training for Stroke Patients to Induce
Use of the Paretic Leg: A Report of Three Cases
Kimitaka Hase, Toshiyuki Fujiwara, Tetsuya Tsuji and Meigen Liu

Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan(Recieved for publication on November 12, 2007)(Revised for publication on January 7, 2008)(Accepted for publication on February 21, 2008)

Abstract. During recovery from a stroke, body weight-bearing on a paretic leg is spontaneously avoided. In physiotherapy for hemiparetic gait, as long as the patients can use their
non-paretic leg, adaptive and compensatory strategies are always used to support and movethe body. We examined the effects of gait training using prosthetics to induce the use of aparetic leg during walking. The prosthesis was applied to the non-paretic leg of three righthemiparetic patients. Prosthetic gait training was performed until finishing 5 successive
motor learning sessions involving walking over 200 m and the changes of asymmetric gait
performances were analyzed. The ground reaction forces during the initial stance phase of
the paretic leg were increased in all patients after prosthetic gait training. Simultaneously,
the propulsive force produced by the paretic leg was increased in 2 patients. By contrast,
another patient developed more use of his non-paretic leg for propulsion corresponding toacquiring stability on the paretic leg, resulting in an improvement in single-support-timeasymmetry. Task-specific effects provided by prosthetic gait training may be able to reorganize the motor strategy for hemiparetic gait by inducing the use of the paretic leg to support
and propell the body. (Keio J Med 57 (3) : 162 －167, September 2008)
Key words: Case report, Stroke, Prosthetics, Rehabilitation, Gait training

Introduction
The common movement pattern in hemiparetic patientsis based on an asymmetric motor strategy to compensate
for functional deficits of a unilateral body. In view ofmotor learning theory, physiotherapeutic efficacy forhemiparetic gait has been obtained from reproducing a
gait performance by assisting impaired functions withvarious devices and repeating it under appropriate training sessions to lead to output-optimization. A recent development of gait assisting devices such as a bodyweight-supported treadmill system1 and gait training
methods such as a task-oriented training program2, 3 improves the functional achievements of hemiparetic gait.
However, as long as hemiparetic patients can use their
non-paretic leg, adaptive and compensatory strategies arealways used to support and move the body.4, 5 While performing pre-ambulation exercises to improve paretic leg

function,6 such as kicking a ball against a wall2 or jumping from a standing position,7 gait training per se thatprovides a task-specific effect by inducing the paretic leg
to support and propel the body should be included in theseries of task-oriented training.
Functional cortical reorganization depends on how
much the paretic limb will be used to perform the required task. Moreover, clinical and neurophysiologicalstudies have suggested that the reduced sensory input
from the non-paretic limb will provide functional improvements of the paretic limb.8 Because the posturalcontrol to maintain the standing posture are mainly basedon the sensory information from below the knee,9 removal of afferent inputs from below the knee of the nonparetic leg may facilitate motor learning in gait performance. Amputees require compensatory motor strategies
by the sound leg to control their standing posture with aprosthesis10 similar to hemiparetic postural control based

Corresponding Author: K. Hase, MD, Ph.D. Department of Rehabilitation Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku,
Tokyo, 160-8582, Japan, Phone: 81-3-3353-1211, FAX: 81-3-3225-6014, E-mail address: khase@sc.itc.keio.ac.jp162Keio J Med 2008; 57 (3): 162 －167

163

Table 1. Patient characteristics and training schedules
Trainingschedules

Patient characteristics
Patients

Age

Sex

Stroke(type/lesion)

Duration(months)

SIAS-m(L/E)

MAS of ankle(ankle clonus)

Total numberof sessions*

1
2
3

42 y
60 y
56 y

male
femalemale

CI/MCA
CH/thalamus
CI/ACA

7
78
43

4-4-3
4-4-4
4-3-2

1 (4-5 beats)
1 (2-3 beats)
1 (sustained)

12 (7)
14 (9)
16 (11)

CI; cerebral infarction, CH; cerebral hemorrhage
ACA; anterior cerebral artery, MCA; middle cerebral artery
SIAS-m (L/E); stroke impairment assessment set-motor of lower extremities [6] is shown in order of hip (hip flexion test), knee (knee extensiontest), and ankle (foot pat test) joint.
MAS: modified Ashworth scale [1] of ankle plantar flexors*; Note that the number of sessions for adaptation training is indicated in the parenthesis.

on non-use of the paretic leg.11 Therefore, by applying a
prosthesis to the non-paretic leg, we may be able to induce use of the paretic leg in hemiparetic gait. In order torealize a forced-use of the paretic leg together with reduced input from the non-paretic leg, we applied a prosthesis to the non-paretic leg in hemiparetic gait training.
In this first clinical trial of prosthetic gait training for 3
hemiparetic patients, raw data of ground reaction force
pattern during gait will be shown to reveal a process ofthe motor learning.
Case Description
To prevent a secondary injury of the paretic leg in thefirst clinical study on prosthetic gait training, hemiparetic
patients who could independently ambulate with a prosthesis even if they underwent amputation of the non-paretic leg12 were enrolled to this study. The inclusion criteria were as follows; (1) no significant perceptual andcommunication disturbances; (2) independently walking
without a cane and orthosis; (3) no pain in the low backand legs; (4) no severe proprioceptive dysfunction. The
degrees of motor score and muscular tonus of the paretic
leg were evaluated by the Stroke Impairment Assessment
Set (SIAS)13 and modified Ashworth scale (MAS),14 respectively. The baseline characteristics of the three enrolled right hemiparetic patients are given in Table 1. Before participating in the study, the patients gave their informed consent to the gait training program using a prosthesis and gait analysis schedules described below.
The prosthesis designed to simulate an amputee’s gait
was used for hemiparetic gait training (Figure 1). Since
muscular overactivity of the non-paretic leg during walking may prevent functional improvements of the paretic
limb,8 the prosthesis was designed to give stability during a period of prosthetic stance. The socket holding thenon-paretic leg in the flexed knee position was prescribed to individual patients. The knee and ankle joints

Fig. 1 A prosthesis applied to the non-paretic leg of a righthemiparetic patient.
The weight of the prosthesis including a socket and custom footdevice is about 2.5 kg in total. To force use of paretic lower limb
in the propulsive (push-off) phase of gait, the forefoot portion of
the custom foot device is cut about 5 cm shorter, and a rocker
bottom is provided to facilitate toe-clear during the early swing
phase of gait.

were fixed at 0° and a custom foot device was made up
of a flat and wide sole, with a rocker bottom to allow
easier toe-clear. As a result, hemiparetic patients using
the prosthesis and a walker with 4 casters would be able
to perform rhythmic gait training by dominantly using
the paretic leg.

Hase K, et al: Prosthetic gait training for stroke patients

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Fig. 2 Force plate data before and after prosthetic gait training
Raw data on the vertical and fore-aft components of the ground reaction forces (GRFv and GRFf-a) from three subjects before andafter prosthetic gait training. Two representative gait cycles beginning with force traces under the paretic foot are shown.

Prosthetic gait training was carried out 2 to 3 times per
week over 5 weeks. In the early training sessions, theprosthetic gait was so strenuous for them that the patientswere asked only to walk with as symmetrical stance durations as possible and keep the trunk upright during
gait. For safety, the physiotherapist supported the pelvis.

The training was stopped when patients were physicallyexhausted or hyperextension of the paretic knee joint occurred during the stance phase. After patients were comfortably able to walk over 200 m in 5 successive training
sessions, the physiotherapist encouraged and facilitatedextension of the paretic limb hip joint during the late

Keio J Med 2008; 57 (3): 162 －167

165

Table 2. Asymmetry and walking velocity before and after prosthetic gait traininga) Kinetic asymmetry
Patients
1
2
3

Braking force
Pre-training Post-adaptation Post-training
1.36
1.33
3.21
2.41
6.69
3.33
0.84
1.20
3.15

Propulsive force
Pre-training Post-adaptation Post-training
0.46
0.49
1.24
0.36
0.37
0.46
1.09
0.72
0.31

b) Kinematic asymmetry
Single-support-time
Step-length
Pre-training Post-adaptation Post-training
Pre-training Post-adaptation Post-training
1
0.80
0.75
0.79
0.99
1.05
1.04
2
0.78
0.84
0.90
1.05
1.21
1.18
3
0.63
0.86
1.01
0.96
1.08
1.00
Note; all of asymmetry ratio are indicated by (paretic data/non-paretic data)

Patientsc) Maximum walking velocity(m/sec)Patients
Pre-training Post-adaptation Post-training
1
1.61
1.59
2.03
2
1.33
1.34
1.54
3
1.15
1.22
1.32

stance phase. After each training, gentle muscular
stretching of the paretic lower limbs was performed,
watching for muscular pain and tonus. The total training
time required was only 15 to 20 minutes including
stretching exercises.
Using force platforms (Model MG-1090, Anima Co.,Tokyo), vertical and fore-aft components of the groundreaction forces, GRFv and GRFf-a, respectively, were
measured over 5 gait cycles during walking without
shoes and any devices at a comfortable speed. Under thesame conditions, spatial and temporal gait patterns wereanalyzed by a 6 m instrumented pathway (GAITRite;
CIR Systems, Inc., NJ). Also the fastest comfortablespeed while walking across a 10 m walkway was measured.
Gait analyses were planned before the training, after 5
successive prosthetic training sessions of over 200 m(called adaptation training), and after 5 subsequent training sessions with physiotherapeutic motor learning. Posttraining evaluations were performed at intervals of morethan 48 hours between each session to estimate the prolonged effects on gait performance.
The GRFf-a traces were divided into the braking andpropulsion phases by the baseline. Each trajectory was
integrated to obtain a total braking and propulsive force
respectively, and the ratio between the forces generated
by the paretic and non-paretic leg was calculated toquantify the force asymmetry. Additionally, step-lengthand single-support-time asymmetry were calculated as asimple ratio of paretic leg to non-paretic leg from the instrumented pathway analyses data.

The motor score and muscular tonus of the paretic leg
were unchanged after training. Figure 2 shows the dataof GRFv and GRFf-a together with cadence for each patient before and after prosthetic gait training. Each figurecontains two representative data sets of different gait cycles. After the training, transient peaks of the GRFv increased in all patients just after heelstrike and backward
components of the GRFf-a during the initial period of
the paretic stance phase.
Patient 1, who had finished an intensive treadmill gait
exercise for 2 weeks before participating in the study,
needed time for a gait cycle after the initial series of
prosthetic gait training. But the successive 5 training sessions with physiotherapeutic motor learning organized arhythmic gait pattern with increased paretic propulsive
forces. The GRFf-a data for patient 2 also showed larger
paretic propulsive forces with increased non-paretic
braking forces after prosthetic gait training. These resulted in increased step length of the non-paretic leg (datanot shown). In contrast, paretic propulsive forces in patient 3 decreased slightly. Simultaneously, the non-paretic propulsive forces increased by a factor of about 1.5.
Table 2 shows the mean values of the kinetic and kinematic asymmetry ratios as well as the maximum walking
velocity for each patient. The asymmetry ratio values
over 1.00 mean a greater measure for the paretic than the
non-paretic leg. The prosthetic gait training increased
braking forces of the paretic leg in all patients. However,the changes in the asymmetry ratio of the propulsive
force differed from patient to patient. The post-training
paretic propulsive force in patient 1 somewhat increased

Hase K, et al: Prosthetic gait training for stroke patients

166

compared with the non-paretic leg. In patient 2, theasymmetry ratio of the propulsive force also gradually
increased, but it remained under 0.5. Most interestingly,
the propulsive force ratio in patient 3 became more assymetrical with increases of the non-paretic propulsive
force. As to kinematic asymmetry, the single-supporttime asymmetry in patient 3 improved and the step
length in patient 2 increased somewhat in the paretic leg.
Consequently, the fastest walking speed markedly increased in all three patients.
Discussion
Task-specific training can induce functionally relevant
adaptive changes in the human brain after focal injury.15
When a stroke patient can reproduce motor performance
to develop the skill, rehabilitative treatments to maximize functional motor recovery of the paretic limb must
be applied. Such effective therapeutic strategies leading
to cerebral reorganization have developed through increasing somatosensory inputs from the paretic limb andreducing ones from the non-paretic limb,8 such as constraint-induced movement therapy for the upper limb.1 6
However, difficulty exists in constraining the movementof the non-paretic leg during bipedal walking and usual
gait training per se may produce an asymmetrical gait
pattern based on compensatory motor strategies.1 7 Indeed, accelerated gait pattern ability which patient 1 relearned through the treadmill gait training before participating in this study depended on the reduced weightbearing on the paretic leg in the push-off phase (Figure
2).
The most common characteristics of hemiparetic gait
are decreased ankle and hip powers to propel the
body.1 8, 1 9 We hoped that the paretic propulsive force
would be reorganized after prosthetic gait training. Thisactually developed in patients 1 and 2, coupled with increased paretic braking force. In contrast, patient 3, who
appears to have difficulty in developing ankle plantarflexor moment due to severer palsy (Table 1), started
to use his non-paretic leg increasingly to produce propulsive force. As a result, his kinetic asymmetry increased,
whereas the temporal asymmetry improved. Indeed, forall of the patients, the adaptation to walk with a prosthesis began with stabilizing the paretic leg against the impact from the floor around the heelstrike. It could be induced by a task-specific effect, to which unavailable
compensatory support of the trailing non-paretic leg witha prosthesis in the double support phase contributed.
Lamontagne et al4, 20 reported that the motor strategy in
non-paretic leg during hemiparetic gait was characterized by a reduced stance phase plantarflexor moment
combined with excessive antagonistic coactivation at ankle and suggested that it may result from an adaptation
for poor postural stability during gait. Through the pros-

thetic gait training, which reduces compensatory movements by the non-paretic knee and ankle joint and sensory inputs from the non-paretic leg, the relearned ability
to control the body weight on the paretic leg thus should
allow the non-paretic leg to generate propulsive force by
the active push-off movement.20
On the other hand, while adapting to walking with aprosthesis, there is a potential risk that patients may learna gait pattern based on paretic knee hyperextension during stance phase, which could hinder a smooth forward
shifting of the body-weight on the paretic leg and predispose to joint or ligamentous injury. In case of forming
dynamic knee instability during the prosthetic gait training, the preparatory exercises to obtain the ability to stabilize the paretic knee in closed kinetic chain such as a
tracking training2 1, 2 2 may be required. Also the normal
joint proprioception would be very important in preventing knee hyperextension movements and in learning anappropriate gait pattern.
Patients who cannot dynamically manage a body-mass
including prosthesis on the paretic leg should be excluded from this training. Because we can control the ankle
motion by using an ankle-foot orthosis, the clinical indications of the prosthetic gait training depend on proximal
motor functions of the paretic leg, that are, the abilities
to voluntarily move a hip and knee joints against gravity.
However, recent advances in an assist-based hemiparetic
gait training such as a body weight-supported system enable stroke patients with a severe palsy to walk rhythmically. The potential application of prosthetics to the assist-based trainings may extend the clinical indicationsof the prosthetic gait training and cause additional effects
to the assist-based hemiparetic gait trainings that mainly
reorganize the rhythmical gait pattern by facilitating improvements of the abilities of the paretic leg to support
the body and control equilibrium during gait.
Even if 1 year passes from the prosthetic gait training
intervention, the 3 patients appear to keep their ability tostabilize the body on the paretic leg in the early stancephase without any trouble of the musculoskeletal system.
They explained the extended effects of the prosthetic gait
training such as increased stability when standing in
moving train or getting into the tub. The long-term effectincluding occurrence of a secondary injury must be evaluated in future study. Also, there is need of clinical trials
to compare with other methods of gait training and toverify the effect on the patient with various severities ofsymptoms.
In conclusion, this report provides evidence indicatingthat the gait training using a prosthesis may reorganize
the motor strategy for hemiparetic gait by inducing theuse of the paretic leg to support and propel the body. It
has to contain the process of physiotherapeutic motor
learning to optimize the gait pattern. The task-specificeffects provided by prosthetic gait trainings may make itKeio J Med 2008; 57 (3): 162 －167

possible for stroke patients to dramatically develop their
gait abilities.

167

11.

Acknowledgment
Supported by Grant-in-Aid for Scientific Research (B)(grant no. 19300193).
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