Dynamic Simulation of Muscle Loading During ARED Squat Exercise on the International Space Station

Loss of muscle mass due to reduced mechanical loading is a critical issue for long duration spaceflight on the International Space Station (ISS) [1]. To address this issue, NASA has developed the Advanced Resistive Exercise Device (ARED) that allows astronauts to perform resistance exercise on the ISS. To minimize force transmission to the ISS, the ARED is mounted to a vibration isolation system (VIS). During squat exercise, ARED rotates relative to the ISS, functioning like a nutcracker to compress the astronaut with a load provided by two vacuum cylinders. Though the ARED is an effective exercise countermeasure device, the extent to which squat exercise on the ISS achieves Earth-equivalent muscle moments remains unknown.