網球平擊式發球結合高球速與內外角落點變化，是比賽時的重要得分技術。目的：本研究目的在結合不同量化動作協調的方法，分析選手在擊出內外角落點發球的動作協調差異。方法：以四名優秀網球選手進行內外角平擊式發球各12球，藉由6臺高速攝影機（240Hz）和動作資料擷取系統記錄參與者發球時全身主要肢段關節的運動學資料。所得運動學資料再透過主成分分析、Logistic迴歸分析，以及相對相位分析來比較內外角差別。結果：發球結果與動作時間無顯著差異，在動作協調部分，主成分分析能以三個成分解釋98％以上的動作變異量，進一步分析其內容與結合相對相位分析結果發現，內外角發球在軀幹和前臂的動作協調有所不同。而Logistic迴歸分析結果除與其他兩種分析結果呼應之外，還特別強調左肩、肘在側向的動作上的差異。結論：內外角的發球差異與力量傳遞和重點肢段的動作協調有所關聯，結合各種分析方法，能對於全身性複雜運動協調有較為客觀深入的認識。

The flat serve is one of the most important skills for scoring due to its speed and placement. The purpose of present study aimed to examine the difference on movement coordination of flat serve with interior or exterior placements by using various quantitative tools. Methods: Four elite tennis players participated to implement flat serves with which the placement were both on interior and on exterior of the serving area for 12 serves each. Six high-speed cameras (240Hz) and one motion capture system record the kinematics data of major joints of whole body during the serving. The kinematics data then were analyzed via principal component analysis (PCA), Logistic regression analysis (LRA) and relative phase analysis (RPA). The results showed that no significant difference was found in accuracy of placement and movement time. For movement coordination however, three components explained more than 98% of variance of movement via PCA. Further examining the results from PCA and RPA revealed that movement coordination of trunk and forehand was different between services of interior and exterior. In addition to corresponding to the results from PCA and RPA, the results of LRA also emphasized the difference of movement from left shoulder and left elbow in lateral direction. Conclusion: The difference of serving interior and exterior was related to transfer of force and the coordination of specific segments. An objective and extensive knowledge comes from combining various methods on coordination quantification.