網球雙手反拍肌肉協調型態之探討：個案研究

Muscle Coordination Patterns During Tennis Double-handed Backhand Strokes: A Case Study

本研究目的在透過表面肌電圖來瞭解網球雙手反拍擊球時，慣用手與非慣用手肌肉協調之型態與在不同時期肌肉活化之程度，以提供雙手反拍動作技巧之參考。以一名前世界排名30名內，右手持拍的前職業女子網球選手為受試對象，檢測左、右手的肱二頭肌、肱三頭肌、屈腕肌與伸腕肌部位。以一部數位攝影機（120Hz）拍攝雙手反拍擊球動作，並透過表面肌電系統（1200Hz）同步擷取肌電圖資料。研究結果顯示：雙手反拍擊球時，慣用手與非慣用手扮演著不同的作用。在加速期時，慣用手的肱二頭肌與肱三頭肌、屈腕肌與伸腕肌皆產生「共同作用」（coactivation） 現象，顯示慣用手在此階段主要在固定肘、腕關節。而非慣用手之肱二頭肌、肱三頭肌肌電在加速期與跟隨前期則有明顯的「三相現象」（three-burst pattern），顯示非慣用手在此階段具向前加速的作用。就各階段肌肉活化程度而言，在準備期時，所有肌肉活化程度皆相當低。在加速期，所有肌肉活化程度皆明顯增加，非慣用手的肱二頭肌、屈腕肌、伸腕肌以及慣用手伸腕肌皆維持相當高的肌電振幅。在跟隨階段，非慣用手的屈腕肌、伸腕肌與慣用手的伸腕肌其肌肉活化程度較高。為了更清楚瞭解雙手反拍技巧與雙手間肌肉協調之機制，未來研究應以更多優秀雙手反拍選手來檢測，以釐清慣用手與非慣用手相互協調之作用。The purpose of this study was to investigate the coordination patterns and amplitudes of surface EMG activation between the dominant and non-dominant arms during double-handed backhand stroke. One former ranked top 30 professional female tennis player participated in this study. The muscles, recorded using surface EMG system, were the biceps, triceps brachii, flexor carpi and extensor carpi muscles of both right and left arms. A digital camera, synchronized with the EMG system, was used to determine the movement phases . From this case study, the result showed that dominant and non-dominant arms demonstrated different functions for double-handed backhand stroke. The biceps and triceps brachii of the non-dominant arm presented a three-burst pattern of EMG activity during the acceleration and early follow-through phases. In contrast, the biceps and triceps brachii of the dominant arm coactivated during the acceleration phase. Similarly, the coactivation existed in the flexor and extensor carpi. It implied that the non-dominant arm might play an essential role to accelerate the arm during the double-handed backhand stroke whereas the dominant arm trended to play a joint stabilizer for increasing accuracy. During preparation, all muscles showed lowest amount of EMG activity. While the muscles activation increased during acceleration. The biceps, flexor, and extensor carpi of the non-dominant arm as well as the extensor carpi of the dominant arm had higher activity. During followthrough, the flexor and extensor carpi of the non-dominant arm and the flexor carpi of the dominant arm had high EMG activity.