不同比賽用軟式網球反彈特性之比較

Comparison of rebound characteristic among soft tennis official game balls

前言：本研究目的在於探討不同比賽用軟式網球於硬地網球場上球反彈的出射角、接觸硬地的力量及球體變形量等差異，藉此釐清不同比賽用軟式網球在硬地網球上的反彈特性，以提供選手在比賽時的參考。方法：利用三種國際正式比賽軟式網球之用球，以軟式網球發球機設定兩種不同發球球路（上旋球及下旋球），並用高速攝影機拍攝當球撞擊至測力板上之出射角、球體反彈後速度、著地停留時間、撞擊力及球體形變量，測力板上覆蓋一般戶外網球場所使用之壓克力面層。結果：本實驗發現台製球（46.2）在於上旋出射角時平均角度皆高於日製球，但日製M品牌球（38.2）在於下旋出射角時平均角度較高於台製球；在反彈後速度方面上旋球以日製K品牌球平均27.8公里表現最佳、下旋球日製M品牌球平均28.5公里表現最佳；在測力板上停留時間三種品牌球達到顯著差異（p<.05）；在上旋撞擊力以台製球平均109.7牛頓為最佳，下旋撞擊力日製M品牌球平均90.6牛頓。結論：不同比賽用軟式網球在不同旋轉方式下有相異的反彈特性，選手及教練應留意正式比賽用球之品牌以及其反彈特性的差異，以對應較正確的戰術策略，發揮球體與場地之間的最大效應，尋求最佳的運動表現。

Purpose: The aim of this study was to compare rebound angle， ball velocity， ground reaction force， and ball deformation among different soft tennis official game balls. Understanding rebound characteristic on hard surface helped to adjust strategy during match. Method: Three major official game balls in international tournament (D-brand， K-brand， and M-brand) were used in this study and were served top spin and back spin by serving machine. The high-speed camera was used to detect rebound angle， ball velocity， impact time， impact force， and ball deformation when soft tennis contacted an AMTI force plat which covered a game surface. Result: D-brand ball has the highest rebound angle about 46.2 º at top-spin condition. M-brand ball has higher rebound angle about 38.2º at back-spin condition compared to D-brand ball. In top-spin condition， K-brand ball has the highest ball rebound velocity about 27.8 km/h， but M-brand ball was about 28.5 km/h in back-spin condition. Impact time has significantly difference among three balls (p < .05). D-brand ball has higher rebound angle about 46.2 º at top-spin condition compared to others. M-brand ball has the highest impact force about 109.7 N at top-spin condition， but M-brand ball was about 90.6 N in back-spin condition. Conclusion: There was different rebound characteristic among soft tennis official game balls. Player and coach should be recognizing it in order to reflecting a proper playing strategy.