優秀標槍選手投擲時槍體受力之三維動力學分析

A 3-D Dynamic Analysis of Applied Forces on Javelin during Final Thrust by an Elite Javelin Thrower

古國宏(Guo-Hong Gu) ； 黃長福(Chen-Fu Huang) ； 蔡於儒(Yu-Ju Tsai)

《大專體育學刊》 8卷2期 (2006/06) Pp. 163-171

https://doi.org/10.5297/ser.200606_8(2).0014

摘要

目的：本研究主要希望能先正確的測出旋轉角度回推算其角速度或角加速度等，再配合動力學逆過程(inverse dynamic)的方式來計算出槍時槍體受力及受力矩。方法：主要使用兩台同步Redlake高速攝影機（擷取頻率：250Hz）拍攝一位優秀標槍選手；另外在槍體上固定三顆不共線的反光點，結合流體力學及動力學逆過程來作三維的力學分析。結果：不同時期槍體受力的方向是不一樣的；在手掌握槍的階段，施力的主要作用方向是在槍縱軸，到了快出槍時，手指末端的施力方向則多改為側向。側向力矩的數值始終比軸向力矩大很多；側向力矩在出槍前0.024sec達最大值24.081Nm，軸向力矩則約在出槍瞬間達到最大值1.31Nm。結論：本方法所測得出來的結果和國外量測出來的結果差距在合理範圍內，且操作上較為簡單及無電線干擾的問題，適合作為未來標槍動力學研究的工具。

關鍵字

標槍 ； 動力學逆過程 ； 力 ； 側向力矩

並列摘要

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.

並列關鍵字

javelin ； inverse dynamics ； force ； lateral torque

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