To investigate the effect of antigravity treadmill gait training (AGT) on gait function, balance, and fall risk in stroke patients.
This study included 30 patients with stroke (mean age, 73 years). All subjects were randomly divided into two groups. The intervention group (n=15) performed AGT for 20 minutes, five times per week for 4 weeks. The control group (n=15) received conventional gait training for the same duration. To assess fall risk, the Tinetti Performance-Oriented Mobility Assessment (POMA) was measured. The Berg Balance Scale (BBS), Timed Up and Go test (TUG), and 10-m walk test (10mWT) were measured to assess dynamic balance. All scales were measured before intervention (T0) and at 4 weeks (T1) and 12 weeks (T2) after intervention.
Results showed that the total POMA score, BBS, and 10mWT scores improved significantly (p<0.05) at T1 and T2 in both groups. The POMA gait score (4.20±1.37 at T1, 4.87±1.36 at T2) and TUG (4.52±4.30 at T1, 5.73±4.97 at T2) significantly improved (p<0.05) only in the intervention group. The changes in total POMA score and BBS of the intervention group (7.20±2.37, 7.47±3.07) improved more significantly (p<0.05) between T0 and T2 than the control group (2.53±2.10, 2.87±2.53).
Our study showed that AGT enhances dynamic balance and gait speed and effectively lowers fall risk in stroke patients. Compared to conventional gait therapy, AGT would improve gait function and balance in stroke patients more effectively.
After the onset of stroke, patients occasionally experience diminished balance and asymmetrical weight support, which provokes secondary problems, such as the loss of functional gait, restriction of movement, and falls [
Antigravity treadmill was developed by the National Aeronautics and Space Administration (NASA) to train astronauts for postural and movement control in space [
This study was a single-blinded controlled trial conducted on 30 stroke patients hospitalized in the outpatient clinic of our hospital. The inclusion criteria were as follows: (1) patients aged ≥20 years, (2) at least 6 months since the diagnosis of stroke, (3) ability to walk for at least 10 min with or without assistance, (4) impaired balance (Berg Balance Scale [BBS] score ≤45), (5) had undergone the conventional therapy but not AGT, (6) medically stable and lack of major cardiovascular or other medical conditions. Patients with serious cognitive impairment (Mini-Mental State Examination score ≤20), those with a history of orthopedic surgery in the past 6 months, and those with a neurological diagnosis other than stroke were excluded. This study was approved by the Institutional Review Board of Gwangju Veteran Hospital (IRB No. 2021-9-2). Each participant signed the IRB approved informed consent form, and the participants’ rights were protected in accordance with the ethical principles of the Declaration of Helsinki.
A total of 30 patients were randomized to two groups, with 15 in the intervention group and 15 in the control group. The intervention group underwent AGT for 20 minutes a day, five times a week for 4 weeks. AGT was designed as a progressive resistance training focused on improving dynamic balance control and stability, where the initial overload was set to 30% of the body weight and then increased gradually. All patients started treatment at 30% load, and if they adapted to training for 5 minutes (confirming no adverse events such as discomfort or blood pressure increase), AGT was gradually increased to 80% of the patient’s body weight. If there was an adverse event, the training was terminated. The control group underwent rehabilitation therapy involving conventional gait training with a therapist with more than 5 years of clinical experience. The control group also underwent training 20 minutes a day, five times a week for 4 weeks.
The antigravity treadmill machine used in this study (Via model; AlterG Inc., Fremont, CA, USA) consists of a treadmill enclosed in a waist-high chamber, an air compressor that controls the internal pressure, and a monitoring screen (
Fall risk was evaluated using the Tinetti Performance Oriented Mobility Assessment (POMA), and balance and gait function were assessed using BBS, Timed Up and Go test (TUG), and a 10-m walk test (10mWT). These four scales were assessed before the intervention (T0), and at 4 weeks (T1) and 12 weeks (T2) after the intervention by a therapist with more than 5 years of clinical experience who did not participate in rehabilitation therapy. The POMA used to assess fall risk comprises two sections, each assessing balance and gait, respectively. The balance section reflects balance while seated or standing, and the other section reflects dynamic balance during gait. The total possible score is 28, with 12 for POMA gait score and 16 for POMA balance score, and a lower total score indicates greater fall risk [
All statistical analyses were performed using the R software, version 4.0.1 (R Foundation for Statistical Computing, Vienna, Austria;
There were no statistically significant differences in general and medical characteristics between the intervention and control groups (
The intervention group showed a statistically significant improvement in the total POMA score across time points, with a score of 13.80±5.43, 19.87±5.83, and 21.00±5.95 at T0, T1, and T2, respectively (p<0.05) (
The control group showed a statistically significant improvement in the total POMA score across time points, with a score of 14.33±4.08, 17.27±4.82, and 16.87±4.19 at T0, T1, and T2, respectively (p<0.05) (
The changes in the total POMA score, POMA gait score and POMA balance score were compared between the two groups at each time point (
The intervention group showed a statistically significant improvement in the BBS score, with a score of 36.13±7.82, 41.87±8.02, and 43.60±7.68 at T0, T1, and T2, respectively (p<0.05) (
The control group showed a statistically significant improvement in the BBS score, with a score of 35.67±8.29, 38.93±8.71, and 38.53±8.41 at T0, T1, and T2, respectively (p<0.05) (
The changes in BBS, TUG, and 10mWT were compared between the two groups at each time point (
The results of this study showed that the total POMA score significantly improved at T1 and T2 compared to that at T0 (baseline) in both intervention and control groups. As mentioned in the inclusion criteria, the patients were able to walk for at least 10 minutes with or without assistance, and all showed muscle strength above fair on the Manual Muscle Test (MMT), and there was no change after treatment.
The intervention group showed significant changes in POMA gait score at T1 and T2 compared to baseline but not in POMA balance score. This may be attributable to the fact that AGT reduces body sway during walking because the joint pressure on the lower limbs while walking is reduced during AGT [
The control group also showed a significant improvement in the total POMA score after gait training, but the intervention group showed a greater change in 12 weeks after training. Thus, we suspect AGT is useful for stroke patients, who require more than two-fold greater energy and time to control their posture due to larger sway and poorer stability in an upright posture compared to normal individuals [
The AGT used in this study was probably more helpful in correcting the gait posture because it visualized the patient’s gait patterns on the monitoring screen during the training. Kurz et al. [
The BBS score statistically significantly improved at T1 and T2 compared to that at baseline in both groups, but the improvement was more significant in the intervention group at T2. This also confirms that AGT produces more lasting effects than conventional gait training.
In this study, TUG and 10mWT were used to assess gait speed, a significant factor associated with fall risk, and 10mWT results significantly improved at T1 and T2 compared to that at baseline in both groups. There were no significant differences in the changes observed between the two groups. However, TUG significantly improved at T1 and T2 compared to that at baseline in the intervention group.
These results may be pertinent to the different methods used for the two tests. While a patient gets up from a chair and walks 3 m upon the “start” cue during a TUG test, a patient begins in an upright position and walks 10 m forward during a 10mWT. Hesse [
This study has some limitations. First, the study sample was relatively small, and a follow-up studies with larger samples would be required. Second, the study sample was predominantly male, and subsequent studies to examine the physical discrepancies between sexes would be helpful. Third, the control group was set to conventional gait training and not placebo or without intervention due to ethical considerations. Therefore, this study did not show a markedly greater change in AGT compared to the control group, and the effect appeared to be more significant 2 months after the end of treatment. Finally, the duration of treatment was relatively short (approximately 4 weeks), and a long-term follow-up was not performed. Future studies should examine the longterm effects of treatment by examining longer treatment durations.
In conclusion, this study showed that AGT enhances dynamic balance and gait speed and effectively lowers fall risk in stroke patients. Therefore, AGT can be a beneficial alternative therapy to conventional gait therapy for improving gait function and balance in stroke patients. However, in the future, studies should perform follow-up tests and observations and include more participants to better examine the long-term effects of the treatment.
No potential conflicts of interest relevant to this article were reported.
Conceptualization: Yoon SR, Ryu SR, Oh KR. Methodology: Yoon SR, Ryu SR, Cho TH. Formal analysis: Lim NN, Im NG, Lee Y. Funding acquisition: Yoon SR, Oh KR. Project administration: Yoon SR, Ryu SR, Oh KR, Cho TH. Visualization: Yoon SR, Ryu SR, Oh KR, Lim NN. Writingoriginal draft: Yoon SR, Ryu SR, Oh KR. Writing-review and editing: Yoon SR, Oh KR. Approval of final manuscript: all authors.
Antigravity treadmill device. The device (Via model; AlterG Inc., Fremont, CA, USA) consists of a treadmill enclosed by a waist-high chamber, an air compressor that controls the internal pressure, and a monitoring screen.
Structure of antigravity treadmill device. The air compressor increases the pressure inside the chamber above the atmospheric pressure, and the resulting pressure differential generates a buoyant force, thereby reducing the patient's weight load inside the chamber.
Changes in the outcome measures: (A) POMA (balance), (B) POMA (gait), and (C) POMA (total). POMA (gait) scores in the intervention group at T1 and T2 improved significantly compared to the control group. POMA (total) scores in the intervention group at T2 improved significantly compared to the control group. *p<0.05, between the intervention and control group by repeated measures ANOVA (contrast). AGT, antigravity treadmill gait training; POMA, Tinetti Performance Oriented Mobility Assessment; T0, before the intervention; T1, 4 weeks after training; T2, 12 weeks after training.
Changes in the outcome measures: (A) BBS, (B) TUG and (C) 10mWT. TUG in the intervention group at T1 and T2 improved significantly compared to the control group. BBS scores in intervention group at T2 improved significantly compared to the control group. *p<0.05, comparison between intervention group and control group by repeatedmeasures ANOVA (contrast). AGT, antigravity treadmill gait training; BBS, Berg Balance Scale; TUG, Timed Up and Go test; 10mWT, 10-m walk test; T0, before the intervention; T1, 4 weeks after training; T2, 12 weeks after training.
Characteristics of participants (clinical features)
Intervention (n=15) | Control (n=15) | p-value | |
---|---|---|---|
Age (yr) | 71.20±6.87 | 74.80±3.67 | 0.088 |
Height (m) | 1.65±0.05 | 1.64±0.07 | 0.605 |
Weight (kg) | 68.87±11.67 | 68.93±10.85 | 0.987 |
BMI (kg/m2) | 25.28±3.86 | 25.69±3.19 | 0.752 |
Post-stroke duration (day) | 1,680.53±1,250.43 | 2,093.67±1,756.66 | 0.464 |
K-MMSE | 25.73±2.99 | 25.07±2.81 | 0.534 |
K-MBI | 79.27±9.89 | 79.87±7.48 | 0.858 |
POMA | 13.80±5.43 | 14.33±4.08 | 0.763 |
Gait | 3.87±2.56 | 4.73±2.43 | 0.350 |
Balance | 9.93±3.15 | 9.60±2.10 | 0.736 |
BBS | 36.13±7.82 | 35.67±8.29 | 0.875 |
TUG | 30.44±22.44 | 30.84±17.96 | 0.957 |
10mWT | 0.40±0.14 | 0.48±0.32 | 0.415 |
Sex | |||
Male | 15 | 14 | |
Female | 0 | 1 | |
Hemiplegic side | |||
Right | 7 | 6 | |
Left | 8 | 9 |
Values are presented as mean±standard deviation.
BMI, body mass index; K-MMSE, Korean Mini-Mental State Exam; K-MBI, Korean version of Modified Barthel Index; POMA, Tinetti Performance Oriented Mobility Assessment; BBS, Berg Balance Scale; TUG, Timed Up and Go test; 10mWT, 10-m walk test; T0, before the intervention; T1, 4 weeks after training; T2, 12 weeks after training.
Comparison between intervention group and control group by repeated-measures ANOVA.
Results in measurements of the participants in the intervention and control groups
Intervention |
Control |
|||||
---|---|---|---|---|---|---|
T0 | T1 | T2 | T0 | T1 | T2 | |
POMA | 13.80±5.43 | 19.87±5.83 |
21.00±5.95 |
14.33±4.08 | 17.27±4.82 |
16.87±4.19 |
Gait | 3.87±2.56 | 8.07±2.81 |
8.73±2.99 |
4.73±2.43 | 6.27±2.66 | 6.00±2.42 |
Balance | 9.93±3.15 | 11.80±3.47 | 12.27±3.51 | 9.60±2.10 | 11.00±2.56 | 10.87±2.39 |
BBS | 36.13±7.82 | 41.87±8.02 |
43.60±7.68 |
35.67±8.29 | 38.93±8.71 |
38.53±8.41 |
TUG (s) | 30.44±22.44 | 25.93±19.63 |
24.71±18.82 |
30.84±17.96 | 29.14±16.84 | 29.16±16.87 |
10mWT (m/s) | 0.40±0.14 | 0.47±0.16 |
0.51±0.20 |
0.48±0.32 | 0.52±0.36 |
0.52±0.38 |
Values are presented as mean±standard deviation.
POMA, Tinetti Performance Oriented Mobility Assessment; BBS, Berg Balance Scale; TUG, Timed Up and Go test; 10mWT, 10-m walk test; T0, before the intervention; T1, 4 weeks after training; T2, 12 weeks after training.
p<0.05, comparison between T0 and T1 by repeated-measures ANOVA.
p<0.05, comparison between T0 and T2 by repeated-measures ANOVA.
Changes in measurements of the participants in the intervention and control groups
ΔT1–T0 |
ΔT2–T0 |
|||||
---|---|---|---|---|---|---|
Intervention | Control | p-value | Intervention | Control | p-value | |
POMA | 6.07±2.46 | 2.93±2.09 | 0.053 | 7.20±2.37 | 2.53±2.10 | <0.001 |
Gait | 4.20±1.37 | 1.53±1.19 | <0.001 |
4.87±1.36 | 1.27±1.03 | <0.001 |
Balance | 1.87±1.64 | 1.40±1.30 | 0.395 | 2.33±1.63 | 1.27±1.33 | 0.060 |
BBS | 5.73±3.08 | 3.27±2.46 | 0.221 | 7.47±3.07 | 2.87±2.53 | <0.001 |
TUG (s) | -4.52±4.30 | -1.71±2.08 | 0.034 |
-5.73±4.97 | -1.68±2.27 | 0.010 |
10mWT (m/s) | 0.07±0.07 | 0.04±0.06 | 0.218 | 0.11±0.11 | 0.05±0.08 | 0.064 |
Values are presented as mean±standard deviation.
POMA, Tinetti Performance Oriented Mobility Assessment; BBS, Berg Balance Scale; TUG, Timed Up and Go test; 10MWT, 10-m walk test; T0, before the intervention; T1, 4 weeks after training; T2, 12 weeks after training.
p<0.05, comparison between the intervention group and the control group by repeated-measures ANOVA (contrast).