網球反拍截擊動作之上肢肌肉活化與動量傳遞之研究

Muscle Activation and Momentum of the Upper Extremity during the Tennis Backhand Volley Stroke

本研究針對上肢各肢段在網球不同反拍截擊動作肌肉活化性程度，以及動量傳遞之分析，藉以幫助我們更了解網球截擊球時肌肉的功能性與動量變化率間的關係。以6位男性全能型網球選手為本研究之受試對象（平均年齡26.5±9.4歲、平均身高173.3±3.8公分、平均體重67.3±11.0公斤以及平均球齡12.5±5.6年。）。利用HiRES三度空間運動分析系統，以六台攝影機收集各受試者截擊時的肢體運動軌跡影像資料；並使用EMG MA－300系統來量測上肢8塊肌群，量化分析優秀的網球選手在不同截擊狀態下的上肢肌肉活化性程度和動量傳遞的變化。本研究所得結果如下：重截擊的球拍角動量在擊球瞬間達到0.19公斤.公尺2／秒。點截擊的前臂在擊球前角動量及線動量都減少，是為了改變擊球後球體的動量與速度，在即將完成擊球時，必須延長球拍與球接觸的時間。在整個反拍截擊過程中，在加速期主要是橈側伸腕肌和肱三頭肌的作用最明顯，這樣的表現可減輕過於活躍的橈側伸腕肌之負擔。橈側伸腕肌比橈側屈腕肌更為活躍，即腕關節的伸張與外展是有助於腕關節的穩定性。研究結果將可提供網球教練在擬定上肢肌力訓練計劃之參考，並強化網球運動員在上肢力量以及精確的控球能力。同時，亦有助於臨床醫師及治療師在網球之運動傷害的診斷及臨床治療。The purpose of this study was to 1) quantify the change of momentum in the upper extremity during the tennis volley; 2) investigate the effects of the backhand volley technique and hand drive type on musculature behavior. Six male tennis players (mean age 26.5 ± 9.4 yrs; height 173.3 ± 3.8 cm; weight 67.3 ± 11.0 kg) with right hand dominant were recruited for this study. The six-camera HiRES Expert Vision motion system (Motion Analysis Corp., Santa Rosa, CA, USA) was used to collect the motion data of the upper extremity and the trunk. The electromyography (EMG) data war collected using MA-300, Motion Lab Systems, Inc., USA) The tennis volley was two volley techniques, punch and drop for backhand drive and the sampling rate was 240 Hz. Ten trials were collected for each technique and drive type for each subject. Each trial lasted for 8 seconds with a 3-minute rest between trials. A custom biomechanical model of the upper extremity was used to compute the three-dimensional (3D) momentum of the trunk and upper extremity. The results showed that the larger angular momentum in the punch volley may indicate that it required greater rotatory momentum to return the ball than the drop volley. In the drop volley, the linear and angular momentum decreased before ball impact﹔it therefore, that in order to change the ball momentum and velocity after the stroke, players have to increase the period of ball impact. In the EMG analysis, the flexor carpi radialis and triceps brachii were most active among all muscles in the acceleration phase. The extensor carpi radilis was more active than the flexor carpi radialis, which shows that the extension and abduction in the wrist joint is helpful for keeping the wrist stable. Understanding the 3D biomechanical behavior of the upper extremity during different types of tennis volleys could allow tennis players and coaches to improve the players performance and prevent injury. It is also helpful for physicians and therapists in the diagnosis of sports injury and clinical treatment.