目的：比較有無施作開跳步動作分別對側向跨步與交叉跨步兩種側向移位方式之影響。方法：以一名優秀大專男子甲組網球選手為研究對象，選手須依左右方向訊號指示施作跨步與碰觸目標物的動作；共進行開跳步側向跨步、無開跳步側向跨步、開跳步交叉跨步與無開跳步交叉跨步四種測試。利用兩塊Kistler測力板 (1000 Hz) 擷取地面反作用力資料，並同步佐以足底開關與目標按鈕分別紀錄跨步腳觸地時機與碰觸目標物的時間。結果：施作開跳步動作後，無論採用側向跨步或交叉跨步的移位方式，皆具有較短的跨步時間與整體動作時間，且在推蹬過程可產生較大的側向地面反作用力峰值，峰值發生的時機亦較早。結論：本個案研究顯示施作開跳步動作後有助於側向移位，惟未來研究應以更多優秀的網球選手進行檢測。

Purpose: This study was to investigate the effect of split-step for lateral movement under lateral step and crossover step. Methods: One male collegiate tennis player was instructed to take a step and reach the target in the direction indicated by the direction signal. Four tasks including lateral step with and without a split-step and crossover step with and without a split-step were investigated. Two Kistler force platforms were used to collect the ground reaction forces. The foot switches and the buttons were used to determine the time when the participant stepped on the ground and reached the target. Results: The participate could reach the target earlier by taking a split-step. Conclusion: In this case study, the split-step increases the velocity of a lateral stepping movement.