| Summary: | 碩士 === 國立臺灣體育大學(桃園) === 運動技術研究所 === 96 === The subject of this study is Yueh-Jeng Lin, a woman athlete in the 2006 World University Weightlifting Championship. The purpose of this study is to investigate the kinematic differences between the clean skill in clean and jerk of woman weightlifting and the front squat, in the hip and knee angles, the horizontal deviation and vertical velocity of barbell axle center, and the angle between the line of left Iliac crest and barbell center, and the vertical plane. In this study, a camera of JVC 9800(60Hz) was used. Also measurement of kinematic data was taken by motion analysis software of 2-D Silicon Coach Pro with a COMPAQ computer. After discussions of the results, conclusions are as the follows：
1. The minimum knee angle of the subject at lowest position of the clean support catch is 38.63 degrees, and the minimum knee angle is 52.48 degrees as for front squat support. The difference is 13.85 degrees. The horizontal deviation of axle center of barbell shows that the horizontal deviation of the clean is 6cm more than the front squat. The result shows that the smaller knee angle of the clean is caused due that knee joints move forward. Moreover, since the horizontal deviation is greater, it causes more effort in lift and then the injury possibility of the knee joint will be greater. To control the angle of the front squat will improve the outcome of the clean.
2. Front squat is to lift the barbell from the stand, then the subject stands still and then squats, the whole action is more stable, therefore, it is not affected by angular velocity of knee joints. Due to acceleration of gravity, the action of the clean is not stable, and causes the smaller angles of knee joints, thus influences muscular force of the leg and causes worse lifting ability. In conclusion, we can use the training of the front squat to improve the skill of clean.
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