A gravity-independent constant force resistive exercise unit.

This study designed, developed and tested a novel, practical, gravity-independent exercise machine, the Constant Force Resistance Exercise Unit (CFREU). A CFREU prototype was designed and built according to National Aeronautic and Space Administration (NASA) hardware and physiological requirements, and was evaluated for potential exercise countermeasure viability. Life cycle data exhibit lower life than required by NASA guidelines; however, current CFREU re-designs are addressing this issue. Electromyography (EMG) data indicate that the CFREU used on the ground and in microgravity during exercise is capable of providing forces on the muscles that are similar to a standard free-weight machine used in gravity. Given the results of this study, the CFREU has proven to be a viable potential resistive exercise countermeasure to the deconditioning of the musculoskeletal system in microgravity.