巩立姣背向滑步推铅球最后用力阶段技术的生物力学分析

Kinematic Analysis of the Last Part in Gong Lijiao's Sliding Step Technique

运用文献资料法、三维摄像和录像解析法、对比分析法,对巩立娇推铅球最后用力阶段技术运动学特征进行分析。结果表明:(1)巩立姣左脚着地时,左腿向抵趾板方向摆动下插积极,左腿几乎伸直,左肩远离抵趾板,形成了良好的侧满弓姿势,但躯干扭转不够充分,左肩内扣控制的不太理想,左腿肌群退让性工作和由退让转为克制性工作能力比较薄弱。(2)最后用力加速准备阶段。右腿运动形式主要是以小腿发力侧蹬、踝关节蹬伸为主并推动右髋向投掷方向运动。该阶段巩立姣两脚站位相对较宽。肩的转动快于髋,肩髋扭转动作保持的不好。(3)最后用力加速阶段铅球速度有两次陡增,但第二次球速增加与右肩再次发力有关。(4)加速阶段,巩立姣铅球位移的距离和所用时间均短于世界优秀运动员和我国第一代运动员。

To apply the kinematic analysis in the last part of Gong Lijiao＇ s sliding step technique using docu- mentation, 3D imaging and video analysis. The result shows that： 1. When the left foot touches ground, the left leg actively moves toward the toe board, and almost stretches straight. The left shoulder is away from the toe board, which forms a good arch shape. But the twist of body trunk is insufficient, and the control of the left shoulder is not satisfactory. The retreat and the conversion from retreat to suppression function of the muscle group in lower left limb are not strong. 2. In the last acceleration part, the primary motion of the right leg is ex- ertion through calf, stretching the ankle and pushing the right hip to move at the throwing direction. The distance between two feet is relatively too ,side. Also, turning of shoulder is faster than the hip, the balance of shoulder and hip is not good enough. 3. There are two sharp increase in the speed of the shot put during the last acceleration part. The second increase in speed is caused by the force on the right shoulder. 4. In the acceleration ses- sion, accelerating distance of the shot put is the shortest, and the accelerating time is the shortest compared with excellent athletes.