B7 Designing of Indoor shoes considered landing impact in Jump motion

Abstract

This paper describes shock attenuation effects for court category shoes. The shock attenuation mechanism has been clarified for running shoes. The attenuation of lower frequency vibration on tibia is effective for the designing comfortable running shoes. On the other hand, it has been known that vibration with the higher frequency range rather than running is excited in court category such as tennis, volley and handball. This is mainly derived from the difference in motions. First, landing after spike jump in volleyball is focused and the ground reaction force, acceleration on tibia, local foot pressures and sole thickness were measured in synchronization. The landing onset is at toe and the contact area spreads to midfoot and heel. The higher frequency vibration is mainly excited at heel contact and the input to player is equivalent with a half sine wave. Secondly, high frequency vibration effects on human are investigated by using the vibration testing system. Therefore it is concluded that human feels a discomfort at the vicinity of 60Hz, which is derived from a chest resonance. At the same time, the heart rate also rapidly increases. These phenomena make a bad influence on players' performance. An attenuation of the higher frequency vibration is one of the important functions in the designing process of the court category shoes.