本研究之主要目的是探討網球平擊及上旋兩種不同發球方式中，下肢各關節、骨盆和軀幹之三維運動學變化，並結合測力板量測地面反作用力，計算出壓力中心後分析其與身體質量中心所形成的力矩及身體質量中心位置及速度之變化率。研究結果發現，平擊和上旋發球最主要差異在於上旋發球較平擊發球產生更多側屈力矩，而此力矩的產生最主要的貢獻來自於身體軀幹的側屈。此外，在二維運動學資料中，上旋發球較平擊發球於加速期時產生較多的膝關節彎曲，同時在骨盆產生較多的後傾，如此可幫助增加發球時之動量產生及傳遞。從測力板的力矩結果發現，平擊發球時，身軀的迴旋和彎曲則著力較少但上旋發球時，軀幹的側彎屈動作有助於球的旋轉並形成彎曲軌跡。

The purpose of this study was to explore the biomechanics of the two different serving patterns-flat serve and spin serve. In conjunction with force plates that helped to measure the ground reaction force (GRF) and worked out the center of pressure (COP), a motion analysis system was used to discover the 3-D kinematic changes of the ankle, knee, hip, pelvis and trunk in the overall serving motion in the study. The moment formed by COP with the whole body center of mass would then be analyzed to investigate the kinematic characteristics of the body. The further understanding of the role of joints in the lower extremity during a serve will provide a reference for motions and techniques of training and teaching, with views to improve serving efficiency and to avoid sports injury.