揮撃加重棒球對軍棒速度、球撞撃後速度 及肌肉活性之影響撞撃能量

Effects of hitting weighted baseball on swing velocity%2C ball batted velocity%2C impact energy%2C and muscle activity

前言：本硏究目的在於探討棒球選手在揮擊加重棒球過程中，對揮棒速度、球撞擊後速度、撞擊能量及肌肉活性之影響，用以驗證揮擊加重球是否適合做爲新式打擊訓練方法。方法：受試對象爲12名世新大學棒球隊選手，以比賽用木棒隨機揮擊正常棒球和2倍重的加重棒球，分別利用十台Eagle紅外線攝影機（250Hz)之 Motion Analysis System分析揮棒速度和球撞擊後速度、Biopac三軸加速規分析球與球棒的碰撞時前導手腕關節之撞擊能量、Biovision肌電儀分析前導手屈腕和伸腕肌群之肌肉活性。結果：⑴揮擊正常棒球和加重棒球時之揮棒速度未達顯著差異(p>.05)，(2)加重棒球的撞擊後速度顯著慢於正常棒球(p<05)，(3)揮擊加重棒球時的腕關節之合加速度最大値顯著大於揮擊正常棒球時(p<05)，（4)揮擊加重棒球時前導手屈腕和伸腕肌群之肌肉活性均顯著大於揮擊正常棒球時(p<05)。結論與建議：結果顯示揮擊加重棒球不會影響擊球前的揮棒表現，但會因球體重量較重，減慢球擊出的速度，並對前臂肌群有較大的肌肉收縮刺激，且對腕關節有較大的負荷；本硏究認爲揮擊加重球的打擊訓練，具有模擬揮擊快球速時的高撞擊能量之效果，並能有效地刺激旋轉腕關節揮棒所需的前臂肌群。

Background: The purpose of this study was to investigate effects of hitting weighted baseballs on swing velocity， batted-ball velocity， impact energy， and muscle activity. It was to examine if weighted baseballs could be used as a new hitting training method. Methods: 12 baseball players were recruited from Shih-Hsin University. They randomly hit normal baseballs and weighted baseballs (two times heavier than a normal baseball) by using the same bat. Motion Analysis System， three-dimensional accelerometer， and surface EMG were used in this study. Results: The swing velocity showed no significant difference between normal and weighted baseballs (p>.05). The batted-ball velocity of weighted baseballs was significantly slower than that of normal baseballs (p