Anti-Gravity Treadmill training is a therapeutic option to help recovering runners return to activity after injury. This current concept paper provides a synopsis of the latest evidence of the biomechanical and metabolic changes that occur with body weight support (BWS) treadmill training, effects of anti-gravity treadmill training on clinical outcomes and clinical case studies in injured runners. Literature searches identified studies with descriptive, experimental and interventional designs and case studies that examined acute and chronic use of anti-gravity treadmills in runners and relevant populations. Laboratory-based studies were included to provide technical considerations for rehabilitation programming. Anti-gravity treadmills use causes reductions in cadence, ground reaction forces (GRF), GRF impulses, knee and ankle range of motion, and vertical stiffness, with elevations in stride duration, flight time, ground contact time, and plantarflexion. Anti-gravity treadmills appear useful across a spectrum of injuries in runners, including postsurgical repair of osteochondral defect, stress reactions (medial tibia, pelvis), and lumbar disc herniation. Runners may preserve aerobic fitness, muscle activation patterns, and muscle mass during recovery compared to traditional rehabilitation protocols. Technical considerations for accurate loading include treadmill frame adjustment to appropriate height to ensure accuracy of level of BWS while running, and monitoring for fast cadence to ensure impact loading rates remain low. Speed or grade can be increased to maintain metabolic demand and fitness while minimizing bone and tissue loading. Monitoring for symptom provocation will guide protocol adjustments to BWS and prescriptions. Once able to run pain-free (sustained or interval) >95% BWS for >30 min, the runner is likely ready to safely transition to ground running. Anti-gravity treadmill training can be considered when available to facilitate smooth transition back to ground running in a conditioned state.
Article cited in： Arthroscopy, Sports Medicine, and Rehabilitation, Vol4, No1(January),2022: ppe141-e149
Article link：https://pubmed.ncbi.nlm.nih.gov/35141546/
Rehabilitation from running-related injury often involves cross-training activities with relatively little or no physical impact to joints to allow the musculoskeletal system to heal without losing cardiorespiratory fitness. These activities can include elliptical training or pool training (deep water running). Over recent years, more scientific evidence is emerging to demonstrate value of anti-gravity training for running rehabilitation. Anti-gravity treadmills use positive air pressure to provide partial body-weight support (BWS), thereby lowering impact forces and metabolic demand of running. In this current concept article, potential benefits of antigravity treadmill training and expected biomechanical and cardiometabolic responses are presented, with technical considerations in program development. Available intervention studies and case reports using BWS treadmills are shared, with sample anti-gravity treadmill protocols specific to rehabilitation in runners.
Anti-gravity treadmills leverage ideas from wellestablished technologies, such as body weight harness systems and underwater treadmills. Although these systems support body weight directly with cables or provide body buoyancy in water, the anti-gravity treadmill uses positive pressure from compressed air in an enclosed air-tight structure. The enclosed system surrounds the lower half of the participant’s body. A treadmill is surrounded over the top by an air-tight enclosed inflatable bag, and the participant wears a special set of shorts that have half a zipper around the hip circumference that then zip into the top of the inflatable bag.3 The inflatable bag is attached at each side to support poles that are parallel to the lateral sides of the zipper and are vertically adjustable set into the outer frame of the anti-gravity treadmill. Vertical adjustment of the frame height allows participants of different heights to use the machine.4 Moreover, a more sensitive adjustment of the body weight support can be provided. Anti-gravity treadmills allow for support up to 80% of body weight.
Conclusions ： Anti-gravity treadmills can provide several therapeutic advantages for running injury rehabilitation, including preservation of aerobic fitness, muscle activation patterns and muscle mass during recovery compared to traditional rehabilitation protocols. Speed or grade can be increased to maintain metabolic demand and fitness while minimizing bone and tissue loading. Monitoring pain symptoms during anti-gravity treadmill training will guide protocol adjustments to BWS and prescription. When pain-free running is achieved at >95%BWS for >30min, the runner is likely ready to safely transition to ground running.