網球拍纖維材質與排列角度對擊球反應之分析

The Impact Analysis of Tennis Rackets Varied with Material Composition and Fiber Arrangement

陳帝佑(Ti-Yu Chen)

指導教授 ： 林德嘉 ； 劉宇

國立臺灣師範大學/運動與休閒學院/體育學系/博士(2001年)

摘要

本研究的主要目的在探討不同網球拍纖維材質與排列角度之振動特徵，並藉由實際握拍方式分析手腕部位所受振動的影響，與反彈球速的差異。實驗中採用八種網球拍，其碳纖維和玻璃纖維比分別為1：0、6：1、5：2和4：3，並分別搭配纖維角度22度和30度之網球拍為主要測試的對象，每支網球拍的重量、網線張力和平衡點皆控制在相同的條件下，進行網球撞擊的測試。振動測試是以Biovision的訊號處理系統和一個Biovision（50g）、一個BioPAC（500g）的加速規進行數據的採集，採樣頻率為10000Hz，網球的撞擊速度約為28m/s；反彈球速比是以高速攝影機收集每次撞擊過程的運動學資料，拍攝頻率為1000Hz。研究結果發現，球和球拍的撞擊過程中，球拍纖維角度30度時之振幅較22度小，且網球拍含碳纖維比例越多，球拍結構體之最大振幅值越小，因此在撞擊過程中球拍損耗較少之力學能，所以有較大的反彈球速比；然而球拍含碳纖維比例越多，對於持拍手腕卻有較大之振幅反應，且手腕測得之對數衰減率亦較大，這反映出手腕承受大部分振動波的能量，因而增加了持拍手臂的負荷，故長時間使用將造成運動員之疲勞反應提早發生。
關鍵詞：網球拍、纖維材質、纖維角度、振動

關鍵字

網球拍 ； 纖維材質 ； 纖維角度 ； 振動

並列摘要

This study aimed at analyzing the vibration of various tennis rackets, which were composed by the mixture of carbon fiber and glass fiber. This study was also to investigate how the wrist joint of the player and rebounding velocity of the ball from each racket were affected by the vibration of the racket. There were eight different kinds of tennis racket, composed by mixing carbon fiber and glass fiber in the ratio of 1 to 0, 6 to 1, 5 to 2, and 4 to 3. The angles of the fiber were arranged in 22 degrees and 30 degrees with respect to the longitudinal axis. The rackets had the same weight, string tension and balance. In this study, one experiment was to monitor the vibration in the grip of every tennis racket and in the wrist joint of participant. The other experiment was to distinguish the coefficient of restitution between the ball and everyone of eight different rackets.
Two accelerometers (1000 Hz) and Biovision system were attached to each racket to acquire the vibratory signals. The impact of the tennis ball was set in the velocity of 28 m/s or so. Peak Motus system with one high-speed video camera (1000 Hz) was used to record the kinematics data and to calculate the coefficient of restitution between the ball and racket. The selected variables in the experiments were tested by two-way ANOVA at a=.05 significant level.
The results of this study indicated that the racket had lower value of max vibratory amplitude for fiber angle at 30 degrees than at 22 degrees. The value of max amplitude on tennis racket grip was significantly decreasing as the content of carbon fiber in the racket was increasing. Therefore, more the component of carbon fiber, the tennis racket would lost less mechanical energy, and had higher coefficient of restitution between the ball and racket. One the other hand, however, the amplitude and the ratio of logarithmic decrement were significantly increasing on the wrist joint as the content of carbon fiber in the racket was increasing. Consequently, this phenomenon indicated that the wrist joint would absorb more vibratory energy from racket made by pure carbon fiber. Thereby, the player would bear extra load in the arm and affect his/her performance in long term consideration.
Key words: racket, material, fiber angle, vibration

並列關鍵字

racket ； material ； fiber angle ； vibration

參考文獻

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