Abstract
The purpose of this study is to investigate the influence of the shoe-sole bending stiffness on a mechanism of changes of ground reaction force (GRF). Five runners who were heel strikers participated and 4 types of shoes which inserted the different resin plate into the sole were used in this study. Several parameters during the support phase in the 2.78 m/s running motion, such as GRF, joint torques, and dynamic contributions and conversion coefficients of the joint torque of the support leg to GRF were calculated as evaluation indices. The results obtained from this study are that 1) the propulsion force just before toe off is the largest in the condition wearing shoe with CFRP, 2) this propulsion force change is caused by the ankle joint torque change, 3) center of pressure on the shoe coordinate system and the vector angle of GRF in the sagital plane, which are related with moment arm at the ankle joint, have different correlations with the ratios of sole local bending angles to the total forefoot bending angle. It is concluded that the consideration of the sole bending stiffness distribution is important to control GRF and COP in the designing process of running shoes.
