優秀標槍選手投擲時槍體受力之三維動力學分析

Abstract

Purposes: According to the javelin rules, a throw is valid only if the tip strikes the ground before any other part of the javelin. Therefore, it is important to control precisely the distribution of applied forces to the javelin for further distance and tip-first landing. Methods: Two synchronized Redlake high-speed cameras (250 Hz) were used to videotape an elite thrower and a javelin with three fixed non-collinear markers. The aerodynamic and inverse dynamics were taken into account in the 3D dynamic analysis. Rerults: When the hand gripped the javelin, the applied force was mainly distributed to the axial direction. At release, the javelin was controlled by distal parts of fingers, and the distribution of force was changed from the axial to the lateral direction. The lateral torque was significantly larger than the axial torque all the phase. The peaks of lateral and axial torques were 24.08 and 1.31 Nm respectively. Conclusions: The results calculated by the inversed dynamics were similar to those by previous research. In addition, the method adopted in this study is simple and has no interference of connecting wire, which could be used for further javelin research.