优秀短跑运动员途中跑时下肢关节力矩及肌群功率分析

Joint Torque and Muscle Power of Lower Limb in Elite Sprinters during Running

目的:量化分析优秀短跑运动员途中跑步态中下肢各关节力矩的贡献成分及下肢肌群的做功情况。方法:采集8名优秀短跑运动员在塑胶跑道上途中跑时完整步态的二维运动学数据(300 Hz)及地面反作用力(1200 Hz)数据,利用环节互动动力学方法分析下肢各关节力矩,并计算各关节角度变化和下肢各关节肌群功率变化。结果:在支撑阶段,主要起控制作用的关节力矩为肌力矩和外力矩。摆动阶段,主要为肌力矩和惯性力矩。在快速跑的完整步态中,髋关节伸肌群、膝关节屈肌群及踝关节跖屈群功率峰值均分别显著高于髋关节屈肌群、膝关节伸肌群及踝关节背屈肌群功率峰值;同时,髋关节伸肌群和膝关节屈肌做正功时功率峰值均显著高于其做负功时功率峰值,踝关节跖屈肌群做负功时功率峰值显著高于其做正功时功率峰值。结论:快速跑时,地面反作用力在支撑期及各环节惯性力在摆动期对下肢运动及各关节肌群的工作性质产生主要影响;短跑训练中,应重视髋关节伸肌群的快速主动收缩(做正功)能力,膝关节屈肌群及踝关节跖屈肌群的快速退让性收缩(做负功)能力的训练。

Objective This paper is to quantify the contributions of joints torque and muscle power of lower limb in elite sprinters during running.Methods 2D kinetic data（300 Hz）and the ground reaction force data（1200 Hz）of complete gait from 8 elite sprinters during enroute running on a synthetic surface track were collected.The approach of intersegmental dynamics was applied to analyze the torque of each joint of lower limb,and then the change in joint angle and muscle power were calculated.Results The muscle torque and contact torque are the main control actions during the support phase.Muscle torque and inertial torque are the main joint torques in the swing phase.In a complete circle of gait during running,the peak values of the powers of hip extensor,knee flexor and ankle plantar flexor are apparently higher than those of hip flexor,knee extensor and ankle dorsiflexor.The peak power of hip extensor and knee flexor during performing positive work is greater than that during performing negative work,whereas the peak power of ankle plantar flexor during performing negative work is greater than that during performing positive work.Conclusion In sprinting,the ground counterforce in the support phase,and the inertia forces in the swing phase play a major role in influencing lower limb movement and working muscle groups around the joints.Special attention should focus on the training of fast active contraction of hip extensor and fast passive contraction of knee flexor and ankle plantar flexor.