Balance maintenance mechanism during support phase in running

Abstract

The purpose of this study was to clarify balance maintenance mechanism during support phase in running. The functional roles of support leg joints and torso joints were analyzed by quantifying dynamic contributions of the joint torques to the generation of angular velocity vectors of the ankle, hip and torso joints in the frontal plane using the equation of whole-body motion. A male runner participated in this research and ran at the speeds of 4 and 3.5 min/km. The trajectories of 47 markers attached to the body and the ground reaction force of the support leg were measured with VICON-MX system with a force plate. The results indicate that 1) the contributions of individual joint axial torques to the angular velocities whose axes are normal to the frontal plane are canceled so as to reduce the angular velocities, 2) the angular velocities are induced by joint torques whose axes are normal to not only frontal plane but also sagittal and horizontal planes, and 3) the balance maintenance mechanism would change when running speed and foot strike pattern change.