目的:在比較不同跳法色括游泳抓台出發、蹲躇跳及下蹲就之下肢在生物力學上的差異。方法:研究對象是五位擁有十年抓台出發經驗的選手(男3位，女2位;年齡24.6土3.2歲) ，研究中使用一台Peak-Performance高速攝影機(拍攝頻率為120Hz)及一台Kistler測力板(600Hz)，將二者同步來擷取所需的資料。地面反作用力和運動學參數分別藉由KistlerBioWare和 Peak Motus 7.0分析軟體得知;另外，經由動力學逆過程數學模型的計算求得 下肢淨關節肌肉力矩及功率。結果:游泳抓台出發動作比蹲躇跳和下蹲跳複雜許多，在下肢運動學方面，抓台出發和下蹲跳都是有膝和躁關節的屈曲再伸展，抓台出發和蹲躇跳在動作期間競關節並沒有先屈曲，而是持續仲展的。在地面反作用力方面，游泳抓台出發的水平地面反作用力曲線是持續上升的(動作一直向前移動)，和蹲蹄跳與下蹲跳完全不同。而在下肢淨關節肌肉力矩及功率方面，游泳抓台出發同樣地和另二種跳法的變化型態不同，尤其以幌關節肌肉群的作用方式最為特別。結論:游泳抓台出發、蹲路跳和下蹲跳雖然都是下肢的Z董仲動作，但人體下肢在抓台出發時的關節肌肉作用型態卻不同於蹲踞跳和下蹲跳;建議教練在指導及訓練抓台出發時應以其關節肌肉群的作用型態來作為肌力訓練的依據。

Purpose: The purpose of this study was to compare the biomechanical characteristics of lower extremities in different jumps including swimming grab start， squat jump and countermovement jump. Methods: Five subjects (3 males and 2 females， age 24.6士3.2)， who have over ten year experiences in swimming grab start， participated in this study. One Peak-Performance high-speed video camera operating at 120 Hz and one Kistler force plate (600Hz) were synchronized to collect data. Ground reaction force and kinematic parameters were derived from Kistler Bio Ware and Peak Motus 7.0 software， respectively. A mathematical model of inverse dynamics was used to calculate net muscle joint moment and power of lower extremities. Results: Grab start movement was more complex than squat jump and countermovement jump. Inthe kinematics of lower extremities， knee and ankle joints in grab start and countermovement jump were in the sequence of flexion， and then extension. Hip joint in grab start and squat jump was constantly in extension. Inground reaction force， the horizontal ground reaction force constantly increased in grab start (subject moved forward constantly). Itwas totally different from other jumps. Innet muscle joint moment and power of lower extremities， grab start also had a different pattern from other jumps， especially in the hip joint. Conclusion: Swimming grab start， squat jump， and countermovement jump were movements involving extension of lower extremity， but the patterns of muscle/joint activation were different. Itis suggested the coaches should rely on the pattern of muscular contraction in training grab start.