Different Temporal Structure of Muscle Synergy Between Sit-to-Walk and Sit-to-Stand Motions in Human Standing Leg

Abstract

Humans do not only perform individual motion separately, but they transit motions from one to another. It has been widely known that human sit-to-stand and walking motions are composed of four and five muscle synergies, but it is not clarified how humans utilize these muscle synergies to generate sit-to-walk motion. This study conducted a measurement experiment to identify muscle synergy structure in standing leg during the sit-to-walk motion. Results showed that the same muscle synergy of sit-to-stand and walking could explain sit-to-walk motion. Three of four synergies in sit-to-stand was not significant different but the last synergy was adaptively changed in order to shorten the time of postural stabilization to initiate stepping motion.