The motor tasks of the running motion are to propel and support the body with counteracting the gravity. The functional roles of support leg joints are braking/propulsion and support of body during the support phase in the running motion. The purpose of this study is to clarify the influence of the running velocity on the dynamic functional roles of the support leg joints in the constant pace running motion. Seven runners, who were heel strikers, participated in this research and ran at the speed of 6, 5, 4, 3 min/km. Dynamic contributions of the joint torque of the support leg to the whole-body's CG acceleration are calculated from a dynamic analysis utilizing the equation of the whole-body motion. The results obtained from this study are that (1) the contribution ratio of the eccentric component of the hip extension torque increased due to the increased torque on the hip joint with increasing running velocity, (2) although the change of the contribution ratio of the knee extension torque was small in the body support direction, the change of the ratio of the eccentric component increased and that of the concentric component decreased with increasing running velocity , and (3) the ankle joint contributions to the body support and propulsion were induced by the increased ankle joint torque and additionally the body propulsion was enhanced by the change of the dynamic conversion coefficient, which transforms joint torque to the whole-body's CG acceleration, of the ankle joint caused from the change in the shank segment angle.
The Proceedings of Joint Symposium: Symposium on Sports Engineering, Symposium on Human Dynamics
