Test and Evaluation of a Zero-G Treadmill Restraint System

Abstract

Manned spaceflight missions result in human exposure to reduced gravity environments, during which the human body undergoes some pronounced physiological changes. Exercise has been identified as a practical and operationally acceptable countermeasure to the physiological responses to “zero-gravity”. At the National Aeronautics and Space Administration's Johnson Space Center, a new treadmill is under development for use on Shuttle flights. One of the main challenges of this project is the development of an effective restraint system. The restraint system must place a body weight load on the subject while the subject exercises in zero-gravity. Additionally, the restraint system must allow the subject to exercise in zero-gravity at various percent grades (treadmill slopes). This paper discusses the restraint system of a prototype treadmill and zero-gravity test results. The results indicate the manually operated, prototype restraint system has some limitations and that a real-time feedback system utilizing a servo operated adjustment mechanism would significantly enhance performance.