从60 cm高度下落到不同硬度的地面下肢关节的力学响应

研究了从60 cm高度下落到2种不同硬度的地面,即木板地面和海绵垫时下肢关节的力学响应.结果表明:人下落到软的地面上时下肢关节的受力、力矩显著减小,关节的角度变化显著增加,从着地到落地停稳所用的时间显著增加.各关节力矩是外力矩与肌肉力矩共同作用的结果,正确的落地技术应该是3个关节的力矩同时减小,掌握正确的落地技术的实质是掌握正确的肌肉被拉伸与收缩的顺序和大小.从60 cm下落着地后,不论是何种地面条件,3个关节的力矩以髋关节力矩为最大,膝和踝关节肌肉是在髋关节控制下起互相协调作用.

THE BIOMECHANICAL CONTRIBUTIONS OF THE LOWER EXTREMITY JOINTS FROM 60 cm HEIGHT TO THE DIFFERENT LANDING

The biomechanical effect of the lower extremity joints from a vertical fall of 60 cm to soft mat and stiff floor landing is ivestigated. The result shows that the lower extremity joints have a significant decrease in joints forces and peak joint moments. The change in joint angles and the time from initial contact until action stop significantly increase. Each joint moment is a effect of both external moment and internal muscle moment. Accurate loading technique proposes that the moments of all segments should be reduced simultaneously. This result suggests that the contraction and passive stretch of muscles must be controlled in order and magnitude. The highest muscle moment is observed at hip joint in both landing conditions after contact landing, the knee and ankle joint muscles assist each other and are assisted by the hip muscles.