Biomechanical relationship between the frame stiffness and pedaling movement in racing bicycles (Improvements of bicycle model)

Abstract

The purpose of this study is to clarify biodynamic relations between the frame stiffness in a racing bicycle and the physical loads of an athlete by using a forward dynamics simulation model. The human body structure was represented by the 13-rigid-links and 21-degrees-of-freedom model. Based on the theory of multibody dynamics, the frame structure was expressed by combination of 16 rigid pipes, and the frame stiffness was modeled by rotational springs at the connecting joint between the rigid pipes. Rolling contact between the bicycle tires and the ground was expressed using a rack and pinion mechanism that converted the rotational motion into translational motion. As a result of reviewing each constraint condition, it was shown that the joint load was reduced in the frame of lower rigidity than in the frame of higher rigidity.