桌球正手弧圈球之運動學

本研究目的在探討一般弧圈球與前衝弧圈球之肩、肘和腕關節之三維運動學參數，並比較不同拉球技術在各分期動作時間上的差異。本實驗招募六位國家級桌球選手，採用三維動作分析系統，拍攝頻率為240 Hz，記錄選手進行正手拉弧圈球和拉前衝弧圈球動作，所得資料透過MATLAB 7.5計算各關節運動學參數，並以無母數魏氏考驗，比較不同拉球動作在選手持拍臂運動學上的差異。本研究結果：前衝弧圈球在後擺期與加速期所耗費時間較短，因此相較於一般弧圈球，選手是以較短的時間完成前衝弧圈球之動作（p<.05）。最大肩關節屈曲與內旋角度、腕關節橈偏與肩關節最大屈曲角速度皆發生在前衝弧圈球（p<.05）。來球旋轉特性影響著選手引拍時間和回擊動作，前衝弧圈球與一般弧圈球在動作上最大的不同之處在擊球前肩關節外旋與軀幹右傾角度。本實驗量化一般拉球與前衝弧圈球上肢之主要差異，研究結果能提供選手與教練，兩種技術的學習或教學上之參考。

關鍵字

前衝弧圈球；上肢；肩關節外旋；軀幹右傾角度

並列摘要

The loop drive is one of the most aggressive skills in table tennis. In general, two kinds of loop drive were often used. One is loop drive which is used against backspin balls; another one is fast loop drive, which is used against topspin balls. The purpose of this study was to assess the kinematics of racket arm in table tennis forehand loop drive and fast loop drive for 6 male advanced table tennis players. In this research the motion analysis system and eight CCD cameras were used to capture three-dimensional motion (240 Hz). MATLAB® was used as tool to compute the kinematics at each joint of racket arm to gain peak angle and velocity. All parameters of this study were compared using Wilcoxon matched-pairs signed-ranks test. The fast loop drive took less time during the back swing and acceleration phase so that players spent less time to finish the whole action, compared with the other one (p＜.05). The peak value of shoulder flexion, internal rotation, wrist radial deviation and peak flexion angular velocity of shoulder were observed in fast loop drive (p＜.05). The specifics of ball spin have impacts on time of back swing and hit back movement. The difference between fast loop drive and loop drive was shoulder external rotation and trunk right bending angle before impact. We assessed the kinematical difference between loop drive and fast loop drive. Thus results from this study could provide useful information about teaching guide and learning reference for coaches and athletes.