緒論：過肩投擲動作為國小體育課教學重點之一，因此瞭解學童經練習後，各關節投擲技巧的掌握度，可讓國小教師實施針對性的教學，以提升學童的投擲動作表現。方法：以8位國小六年級學童，進行為期六週的過肩投擲練習，透過兩台高速攝影機（CASIO EX-F1, Japan, 300Hz）同步收取練習前、後慣用側腕、肘、肩、髖、膝與非慣用側膝關節之運動學參數。再以動作分析軟體（Kwon3D 3.01, MIE Medical Research, Korea），分析離手球速、各關節最大角度與角速度，以IBM SPSS 23.0統計軟體，透過成對樣本t檢定（paired sample t test）考驗練習前、後之各關節運動學參數差異；再以皮爾森積差相關（Pearson product-moment correlation coefficient）檢驗各參數相關性，統計水準訂為α = .05。結果：練習後離手球速、各關節最大角度與角速度，除髖關節外，均顯著優於練習前。此外，練習後離手球速與上肢腕、肘關節之最大角度與肘關節、雙腳膝關節最大角速度皆達顯著的正相關。結論：經六週練習後，學童逐漸掌握過肩投擲技巧，但對於肩關節旋轉與髖關節向前屈曲的運用，尚未完全掌握。由此可知學童過肩投擲模式，學習之掌握順序以四肢為優先，軀幹部分則掌握的較慢，建議國小教師在實施過肩投擲課程時，除給予學童充分的練習外，可多著重於肩關節旋轉與髖關節向前屈曲的指導與示範，藉此讓國小學童能更快掌握投擲技巧。

Introduction: Overarm throwing is one of the key element in physical education classes of the elementary school. Teachers will be allowed to implement specific teaching methods and improve the throwing performance of children by understanding how children mastering throwing skills after practice. Methods: Eight sixth grade students completed a 6-week overarm throwing practicing program. Kinematic parameters of dominant lateral wrist, elbow, shoulder, hip and knee joints and the non-dominant knee joint were recorded by two high speed cameras (CASIO EX-F1, Japan, 300Hz) before and after program. The motion analysis software (Kwon3D 3.01, MIE Medical Research, Korea) was used to analyze the maximum angle, angular velocity and releasing speed of each joint during the movements. The data analyzing were using IBM SPSS 23.0 statistical software. Paired sample t-test was used to examine the differences of each parameter between before and after the program. Pearson product-moment correlation coefficient was used to verify the correlation between each parameter. Statistically significant level set at α = .05. Results: After the program, the releasing speed was significantly faster than before. Except for the hip joint, both the maximum angle and the angular velocity of each joint were significantly improved. Besides, releasing speed was significantly positive correlated to the maximum angle of wrist and elbow joint and angular velocity of elbow joint. The maximum angular velocity of both knees were significantly positive correlated to elbow joint. Conclusion: After six weeks practice, students gradually mastered the throwing skills. However, the movements of shoulder rotation and hip bending forward during throwing were not fully mastered. It reveals that the learning pattern of overarm throwing in children gave the priority to the limbs over trunk. Consequently, it suggested that teachers need to strengthen the guidance and demonstrations on rotation of the shoulder joints and the hip forward movements when implementing an overarm throwing courses. Thereby enable elementary students to master throwing skills as fast as they can.