緒論：舉重運動中，槓鈴軌跡（barbell trajectory）是教練與選手重點關注的話題，可從其中觀察選手試舉時的槓鈴軌跡變化，以利於調整選手技術動作並提高試舉成功率，然而過去研究較少比較挺舉成功與失敗試舉之間的槓鈴軌跡差異，因此造成挺舉失敗之原因，是目前值得探討的問題。目的：比較挺舉各分期槓鈴偏移距離之差異。方法：本研究使用一臺Sony數位攝影機，拍攝頻率為每秒60張，以記錄26位男子運動員之挺舉試舉。影像收集完畢後，利用影像分析技術獲取槓鈴軌跡，並使用配對t檢定（paired t-test）比較成功與失敗試舉之差異。結果：在上搏階段中，發現接槓期的水平偏移距離呈現顯著差異（p=.047），且成功試舉的偏移距離顯著小於失敗試舉。另外，在上挺分期發現，下蹲期（p＜.01）與驅動期（p=.04）的垂直偏移距離，皆為成功試舉顯著大於失敗試舉，其餘分期皆未觀察到有顯著差異性。結論：臺灣成年男子運動員挺舉主要失敗原因為，上搏接槓期產生過多水平偏移距離，浪費多餘體力再修正槓鈴軌跡上，影響後續上挺運動表現。此外，上挺下蹲距離不足，會減少上挺驅動期垂直高度，使運動員無法有足夠的高度完成接槓，最終導致試舉失敗。

Introduction: The barbell trajectory in weightlifting is a focus of both coaches and weightlifters. Observation of the barbell trajectory during lifting can help weightlifters to adjust their movements and improve the success rate of lifts. However, previous studies have rarely compared differences in barbell trajectory between goodlift and nolift in the clean and jerk. We believe that the reason for the failure of the clean and jerk is worth investigating. Purpose: This study aimed to compare barbell travel distance and velocity in different stages of the clean and jerk. Methods: We used a Sony digital video camera at 60 frames per second to record the clean and jerk of 26 male weightlifters. The barbell trajectory was obtained from the videos. The paired t-test was used to compare the differences in trajectory between goodlift and nolift. Results: In the clean stage, the horizontal travel distance of the catch was significantly different between goodlift and nolift (p = .047), and the distance of goodlifts was less than that of nolifts. In the jerk stage, the vertical travel distance of goodlifts between the jerk dip (p < .01) and the jerk drive (p = .04) was significantly greater than that of nolifts, while no significant differences were observed in the other stages. Conclusion: The main reason for the failure of the clean and jerk among Taiwanese adult male athletes is the generation of excessive horizontal travel distance during the catch. Under this condition, athletes may waste power on modifying the barbell trajectory, which affects the subsequent performance of the jerk. In addition, insufficient jerk dip vertical distance reduces the vertical height during the jerk drive, thereby preventing the athlete from gaining sufficient height to complete the catch, which eventually leads to failure of the lift.