Keywords：Treadmill training，Walking，Anti-Gravity Treadmill，Locomotor training
Source of literature：The application of antigravity treadmill training to clinical rehabilitation: A systematic review and meta-analysis[J]. Gait & Posture, 2025.
Author of the document：Jie Hao, Zixuan Yao , Andreas Remis , Na Ye , Yuxiao Sun ，Dongqi Zhu, Kangchao Wu, Yao Yao
1. Research Background & Objectives
This meta-analysis, jointly completed by rehabilitation teams from China, the United States and Australia, was published on Gait & Posture (2025), an authoritative journal focusing on gait and human locomotion. The research protocol was registered on PROSPERO with registration number CRD42024517411.Walking function is a core determinant of mobility and general health. Injuries or lesions of neuromuscular and musculoskeletal systems severely damage patients’ balance, gait and lower-limb performance. Conventional locomotor rehabilitation includes overground walking, aquatic therapy, standard treadmill training and robotic partial body weight support treadmill, which are limited by excessive joint load, distorted gait patterns and restricted training intensity.Derived from NASA’s zero-gravity astronaut training technology, the Anti-Gravity Treadmill relies on a sealed inflatable positive-pressure chamber around the waist to precisely reduce weight-bearing ratio (minimum 20% of body weight). It enables patients who cannot bear full weight to perform gait training close to natural physiological patterns. The first commercial Anti-Gravity Treadmill obtained FDA medical certification in 2008 and has been widely adopted by rehabilitation institutions worldwide.To fill the gap of integrated quantitative evidence across diverse patient groups, this study systematically screened, critically evaluated and quantitatively synthesized all existing clinical trials, delivering evidence-based guidance for standardized clinical application of Anti-Gravity Treadmill training.
2. Research Methodology
1.Literature Retrieval: Three core databases (PubMed, Embase, Scopus) were searched from inception to May 1, 2024. Only peer-reviewed English human clinical trials were included; conference abstracts, case reports, cross-sectional and qualitative studies were excluded.
2.Eligibility Criteria: Participants with motor function deficits; intervention = Anti-Gravity Treadmill rehabilitation; comparators = conventional therapy, standard treadmill, overground gait training, aquatic exercise; primary outcomes covering balance, gait speed, walking endurance, lower-limb function, pain and biomechanical gait parameters; study designs: randomized controlled trials (RCTs) or single-cohort clinical trials.
3.Screening & Quality Assessment: Two independent researchers completed title/abstract screening, full-text data extraction and bias evaluation, with disputes resolved by a third reviewer. RCT quality was scored via PEDro scale (score 6–8 = good quality); single-cohort trials were assessed by NIH Study Quality Assessment Tools.
4.统计学分析：采用RevMan5.4开展Meta分析，以标准化均数差SMD作为效应量；异质性I²＞50%采用随机效应模型，P＜0.05视为差异具备统计学意义；效应量判定标准：小效应0.2–0.5、中等0.5–0.8、大效应＞0.8。
3. Key Results
A total of 595 records were initially retrieved, and 24 eligible trials involving 682 patients were finally enrolled after duplicate removal and full-text screening, including 15 RCTs and 9 single-cohort trials, all using Alter-G Anti-Gravity Treadmill systems.
3.1 Subjects & Training Protocols
3.1.1 Neuromuscular disorders: stroke, Parkinson’s disease, cerebral palsy, diabetic polyneuropathy, multiple sclerosis, muscular dystrophy, Charcot-Marie-Tooth disease;
3.1.2 Musculoskeletal conditions: knee osteoarthritis, total knee arthroplasty, post-operative hip/tibial/pelvic/ankle fracture;
3.1.3 Training parameters: single session 20–60 mins, 2–6 sessions per week, total intervention cycle ranging from 2 weeks to 3 months. Weight-bearing load was progressively increased starting from 20% body weight; training modes included aerobic exercise, lower-extremity strengthening, rhythmic gait and high-intensity locomotor variants (jogging, side steps, skipping). Control groups received traditional physical therapy, land walking, standard treadmill or aquatic rehabilitation.
3.2 Safety Outcome：No adverse events related to antigravity treadmill training were documented in all 24 trials, proving the intervention possesses excellent safety for clinical use.
3.3 Quality Evaluation
3.3.1 15 RCTs: 13 trials were graded good (PEDro score 6–8), 2 trials fair (score 5). Blinding of participants and therapists was impossible due to device characteristics; only 7 trials implemented assessor blinding. Deficiencies existed in follow-up duration and intention-to-treat analysis in partial studies.
3.3.2 9 single-cohort trials: 3 trials rated good overall quality, 6 rated fair. Common limitations included small sample sizes, lack of sample size calculation basis and high follow-up loss rate.
3.4 Quantitative Meta-Analysis Outcomes
3.4.1 Patients with Neuromuscular Diseases
3.4.1.1 Balance capacity: significantly greatly improved (SMD=1.78, 95%CI 0.93–2.64, P＜0.001, large effect size);
3.4.1.2 Gait speed: statistically significant enhancement (SMD=0.90, 95%CI 0.10–1.70, P=0.03, large effect size);
3.4.1.3 Gait endurance (6-minute walk test): showed improvement tendency without statistical significance (SMD=0.41, P=0.06), possibly caused by insufficient sample size and statistical power.Stratified subgroup results: For stroke survivors, antigravity treadmill training outperformed standard treadmill in regulating gait temporal parameters and lower-limb muscle activation; it generated comparable benefits to aquatic treadmill while achieving superior walking endurance. For children with cerebral palsy, stride length and cadence improved more remarkably than harness-supported partial weight-bearing treadmill. High-intensity antigravity gait training relieved freezing of gait and boosted overall motor function among Parkinson’s patients.
3.4.2 Patients with Musculoskeletal Injuries
3.4.2.1 Gait performance: extremely significant large improvement (SMD=2.99, 95%CI 1.66–4.33, P=0.006);
3.4.2.2 Patient-reported lower-limb function (WOMAC/KOOS): significant large enhancement (SMD=1.55, 95%CI 0.58–2.52, P=0.002);
3.4.2.3 Pain intensity: significant large pain reduction (SMD=-1.59, 95%CI -2.39~-0.79, P＜0.001, large negative effect size).Stratified subgroup results: For knee osteoarthritis (including overweight patients), weight-unloading training alleviated joint inflammatory pain and strengthened quadriceps. Post hip/lower-limb fracture training mitigated muscle atrophy and elevated isokinetic strength of hip extensors. Non-operatively treated pelvic fracture patients recovered normalized gait patterns and relieved pain effectively. After total knee arthroplasty, Anti-Gravity Treadmill achieved equivalent rehabilitation effects to overground training with better early-stage intervention tolerance via controllable weight load.
3.5 Advantages vs. Conventional Rehabilitation
3.5.1 Versus harness partial weight-support treadmill: No harness constraint to distort three-dimensional gait, muscle activation patterns are more consistent with natural walking;
3.5.2 Versus aquatic therapy: Delivers equivalent weight-unloading effects with lower site and maintenance costs, free from space limitations of therapy pools, supporting precise gradient quantification of training load.
4. Discussion, Limitations & Conclusions
4.1 Therapeutic Mechanism
Anti-Gravity Treadmill enables task-specific, high-repetition gait training to facilitate neural plasticity. Gradational controllable unloading reduces plantar pressure and limb load, allowing high-volume, high-intensity rehabilitation practice for patients with balance deficits, unilateral weakness and peripheral neuropathy.
4.2 Research Limitations
The total number of included trials and sample size of single studies were limited, leading to potential type II statistical error. Only English publications were retrieved, resulting in language publication bias. Heterogeneity existed across trials in diagnosis, injury severity and training dosage, preventing further subgroup stratified analysis.
4.3 Overall Conclusion: Antigravity treadmills are a safe and efficient new type of rehabilitation equipment that can significantly improve balance and gait speed in individuals with nerve damage, while also greatly alleviating pain after orthopedic surgery/arthritis, optimizing gait and lower limb function. It can serve as an enhancement to traditional rehabilitation methods. Current evidence shows its efficacy is comparable to hydrotherapy and suspension therapy, and it is more adaptable to different locations. Further large-scale, multi-center randomized controlled trials are needed to further clarify the optimal training programs for different diseases, identify the most beneficial patient subgroups, and provide stronger evidence-based support for medical institutions’ equipment procurement and clinical rehabilitation program development.
Original document address：https://pubmed.ncbi.nlm.nih.gov/40819630/