Anti-Gravity Treadmill Facilitates Knee Surgery Recuperation

A new study describes how a graduated return to running using an anti-gravity treadmill can enhance self-efficacy and subjective knee function.

Researchers at the University of Kent (Canterbury, United Kingdom) reported the case study of a 39-year-old healthy female endurance runner who suffered from a left knee femoral cartilage defect, for which she underwent arthroscopic microfracture surgical repair using bone marrow aspirate concentrate. Following surgery, an AlterG (Fremont, CA, USA) anti-gravity treadmill was used to manipulate loading during her graduated phased return to running over a period of eight weeks.


During the study, self-efficacy was evaluated using the Self-Efficacy for Rehabilitation outcomes scale (SER) and the Knee Self-Efficacy Scale (K-SES). Subjective knee function was evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee Subjective Knee Form (IKDC). The results showed improvements in SER (57%), K-SES present (89%) and K-SES future (65%) self-efficacy domains. IKDC score increased from 62.1 to 86.2, a 39% increase. The study was published on June 8, 2017, in Physical Therapy in Sport.

“This case report illustrates the importance of considering self-efficacy in rehabilitation after knee osteochondral surgery, and highlights the potential role for anti-gravity treadmills in enhancing self-efficacy and subjective knee function in preparation for a return to sport, “ concluded lead author Karen Hambly, PhD, and colleagues of the School of Sport and Exercise Sciences. “Devices like the anti-gravity treadmill enable walking or running without the full weight of the body, reducing the load on the joints in the lower limbs and bridging the gap between rehabilitation and return to sport.”

The anti-gravity treadmill was originally invented by Robert Whalen, a biomechanics researcher at NASA Ames Research Center, to help astronauts train in space. The original design encloses a treadmill and the astronaut's lower body in an airtight chamber; lowering the air pressure inside the chamber pushed the astronaut down, simulating gravity, allowing exercise at normal Earth weight. For Earth-bound users, the technology is reversed to take the weight off of rehabilitation patients recovering from leg and foot injuries.

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