Intermittent muscle activity in the feedback loop of postural control system during natural quiet standing.

ABSTRACT: The origin of continual body oscillation during quiet standing is a neural-muscular-skeletal closed feedback loop system that includes insufficient joint stiffness and a time delay. Thus, muscle activity and joint oscillations are nonlinear during quiet standing, making it difficult to demonstrate the muscular-skeletal relationship experimentally. Here we experimentally revealed this relationship using intermittent control theory, in which non-actuation works to stabilize the skeletal system towards equilibrium. We found that leg muscles were activated/inactivated when the state point was located in the opposite/same direction as the direction of anatomical action, which was associated with joint torque actuating the body towards equilibrium. The derivative values of stability index define

SUBMITTER: Tanabe H 

PROVIDER: S-EPMC5587544 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature