桌球反拍拉球之生物力學分析

Abstract

本研究以八名臺灣大專甲組男子桌球選手(年齡23±5.0歲、身高172.5±.6.2公分、體重67.1±11.2公斤、球齡13.2±2.7年)為對象，目的在分析來球為上旋及下旋時擊出斜線及直線之反拍拉球動作的各項運動學參數，以瞭解反拍拉球的機轉與特性。研究方法以10部Vicon MX13+紅外線高速數位攝影機(250Hz)擷取動作資料再以Vicon Nexus 1.4及Visual 3D動作分析軟體及Excel軟體計算所需的參數資料。統計處理是以SPSS 19.0版無母數弗里曼二因子等級變異數分析檢定各動作之間的差異，並使用Excel進行事後比較，顯著水準定為α = .05。研究發現大專甲組男子桌球選手在實施反拍拉球動作時，有相似的擊球高度與動作時間百分比；拉下旋球比拉上旋球除需要較低的身體重心外，也需要較大的擊球揮拍速度、揮拍軌跡角度及擊球拍面角度。肩髖軸在引拍期拉下旋的轉動角度大於拉上旋；而在揮拍擊球與跟隨期，拉斜線的肩髖軸轉動角度大於拉直線球。在上肢及下肢關節角度與角速度，拉下旋大於拉上旋及拉斜線大於拉直線。本研究發現，反拍拉下旋球必須具備較多的準備動作與較快的揮拍速度；拉斜線球比拉直線球有較多的軀幹與肢段關節的旋轉角速度。

The purpose of this study was to investigate the kinematical variations among the backhand drive in diagonal and straight line when receiving backspin and topspin services. Eight male collegiate elite table tennis players(age: 23±5yrs, hight: 172.5±.6.2cm, weight: 67.1±11.2kg, experience: 13.2±2.7yrs) in Taiwan were served as the participants. Ten Vicon Motion Capture systems MX13+ (250 Hz) were used to collect the movements of backhand drives, and the Vicon Nexus 1.4& Visual 3D soft ware were used to calculate the kinematic parameters. All the variables were tested by Friedman two-way analysis of variance of non-parametric statistical test which was calculated by SPSS 19.0, and the significant levels as α = .05. The results as follows: The elite collegiate male table tennis players performed backhand drive with the similar height and the similar percentage duration time in diagonal and straight line when receiving backspin and topspin services. It’s not only need lower COM, but also needed the greater racket velocity, swing trajectory angle and racket tilt angle of the contect point in receiving backspin than topspin services. In backswing phase, the rotation angle of shoulder and hip axis were greater in receiving backspin than receiving the topspin services. In the swing phase, the shoulder and the hip axis rotation angles in returning drives to the diagonal were greater than to the straight line. In the joint angle and angular velocity of the upper and lower extremities, due to different spin and direction variations, the main trend showed that the drives for receiving backspin was greater than the topspin; driving return in diagonal were greater than the straight line. Base on the results of this study, we recommen that the table tennis players should increase the preparation movement and ball initial velocity to perform the drives to receive the backspin serves than receive the topspin serves. The players should increase the trunk rotation angle, trunk angular velocity and the angular velocities of the upper and the lower limbs to perform the diagonal line drives in the table tennis game.