Publication:

抓舉試舉成功與失敗之生物力學分析

本研究目的為比較抓舉試舉成功與失敗動作之差異，並探討試舉失敗的原因，以8名國立臺灣體育運動大學男子舉重隊員為研究對象，試舉個人最佳成績90%的重量三次，藉由兩部數位攝影機拍攝抓舉動作表現。選取每位受試者的試舉成功與失敗動作，利用動作分析系統進行三度空間數位化處理與資料修勻後，再計算各項運動學資料；最後經由相依樣本t檢定考驗試舉成功與失敗動作之差異。研究發現，試舉成功與失敗在槓鈴運動學上，第一次拉結束點的垂直速度、槓鈴最大垂直高度與標準化最大垂直高度達顯著差異(p<.05)；在肢體動作上，離地瞬間的上臂與垂直軸之夾角、第一次拉結束點的上臂與軀幹之角度、第二次拉結束點的上臂與前臂之夾角的角速度、第二次拉結束點的髖關節角度、髖關節最大角度、膝關節與踝關節最大角速度、身體重心“近”運動型態之水平位移、槓鈴-身體重心最大垂直高度差，皆達顯著差異(p<.05)。造成試舉失敗的原因，為選手將槓鈴拉離地面時的上臂與垂直軸之夾角過大以及第一次拉結束點的上臂與軀幹之夾角過大，使得槓鈴在第一次拉的垂直速度較慢，而身體重心向前移動接近垂直參考線，加上第二次拉階段的下肢伸展不足，造成槓鈴最大垂直高度較低，使得下蹲支撐空間的不足，造成試舉失敗。

The purpose of this study was to compare the difference of the technique performance between the successful and unsuccessful snatch lifts, and to investigate the case of the unsuccessful snatch lifts. The study was performed on 8 weightlifters of the National Taiwan University of Physical Education and Sport. Two cameras were used to record the three lifts at 90% of 1 RM. Subsequently, for 3-dimensional kinematical data were selected the first lifts both of the successful and unsuccessful snatch lifts on the same lifter, and then to digital and filter the raw data by using the motion analysis system. Finally, the differences between the successful and unsuccessful lifts during the snatch technique were analyzed the t-test for dependent sample. The results showed that the vertical velocity of the barbell at the ends of the first pull, the maximum vertical height of the barbell and normalized maximum vertical height of the barbell were significantly difference (p<.05) at the barbell kinematics between the successful and unsuccessful snatch lifts. At the limb of the motion, the angular of the upper-arm relation to the vertical axis at the lift-off moment at the frontal plane, the angular of the upper-arm relation to the trunk at the ends of the first pull, the angular of the upper-arm relation to the forearm at the ends of the second pull, the angular of the hip joint at the ends of the second pull, the maximum angular of the hip joint, the maximum angular velocity of the knee joint and maximum angular velocity of the ankle joint, the toward of the horizontal displacement on the body of CM, the difference by the maximum vertical height of the barbell-body CM were significantly difference (p<.05) between the successful and unsuccessful snatch lifts. The causes of the unsuccessful lifts were performed the wide range of the maximum angular of the upper-arm relation to the vertical axis at the lift-off moment at the frontal plane, and then to increased the upper-arm relation to the trunk at the ends of the first pull. On the contrary, it was making the slow of vertical velocity of the barbell at the ends of the first pull. And unable to obtain the effective of the initial velocity when the barbell was lift-off the floor, and to caused the body of CM to moving forward the vertical reference line. Finally, due to the lower limb motion are performed poor, and to cause the maximum vertical height of the barbell and lead to the distance of the support the barbell was unable to obtain in it.