Interaction between pre-landing activities and stiffness regulation of the knee joint musculoskeletal system in the drop jump:: implications to performance
Interaction between pre-landing activities and stiffness regulation of the knee joint musculoskeletal system in the drop jump:: implications to performance
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DOI：
10.1007/s00421-002-0673-6
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发表时间：
2002-11-01
影响因子：
3
通讯作者：
Kyröläinen, H
中科院分区：
文献类型：
--
作者：
Horita, T;Komi, PV;Kyröläinen, H
本研究的目的是探讨落地前活动与膝关节肌肉骨骼系统的刚度调节和起跳速度之间的相互作用。9名健康男性受试者从50 cm高度进行DJ测试。记录股外侧肌（VL）的表面肌电图（EMG）活动，以评估着陆前和着陆后肌肉激活水平。用高速摄像机（100帧）同时记录跳跃运动和地面反作用力。s（-1）），并采用测力平台进行联合力矩分析。通过膝关节力矩/角度关系的线性回归计算关节刚度。在DJ过程中的膝伸肌的弹性估计通过一个四元件的肌肉模型，包括一个平行的弹性组件，一个系列的弹性组件（SEC），一个粘性阻尼器，和一个可收缩的元素。DJ成绩与膝关节正峰功率（P < 0.01）和伸展终了时膝关节力矩（P < 0.01）呈正相关。然而，DJ的表现与踝关节的正峰值功率之间没有显著的关系。伸展结束时膝关节力矩与从初始撞击结束到同心动作开始的传递阶段的SEC刚度相关（P < 0.01），与膝伸肌等长肌力发展的最大速率相关（P < 0.01）。多元回归分析显示，膝关节传递阶段SEC僵硬度可由VL肌预活动和触地时膝关节角速度共同解释（F = 5.76，P < 0.05）。这些结果似乎强调了预编程活动的功能意义，用于控制随后的刚度调节，然后有助于在DJ的性能。因此，它可以表明，中央预编程的活动和相关的弹性行为的SEC在膝伸肌与肌肉收缩性能一起发挥了重要作用，在调节DJ的性能。
The purpose of the present study was to investigate the interaction between the pre-landing activities and the stiffness regulation of the knee joint musculoskeletal system and the takeoff speed during a drop jump (DJ). Nine healthy male subjects performed a DJ test from the height of 50 cm. The surface electro-myographic (EMG) activity of the vastus lateralis (VL) muscle was recorded to evaluate both the pre-landing and post-landing muscle activation levels. Simultaneous recording of the jumping motion and ground reaction force was performed by a high-speed video camera (100 frames(.)s(-1)), and a force platform was employed to allow joint moment analysis. Joint stiffness was calculated by a linear regression of the knee joint moment/ angle relationship. Elasticity of the knee extensor muscle during DJ was estimated by means of a four-element muscle model consisting of a parallel elastic component, a series elastic component (SEC), a viscous damper, and a contractile element. DJ performance correlated positively with the positive peak power of the knee joint (P < 0.01) and with the moment of the knee joint at the end of stretch (P < 0.01). However, there was no Significant relationship between DJ performance and the positive peak power of the ankle joint. The knee joint moment at the end of stretch correlated with the SEC stiffness during the transmission phase from the end of the initial impact to the onset of the concentric action (P < 0.01) and with the maximum rate of isometric force development of the knee extensors (P < 0.01). Multiple regression analysis showed that the SEC stiffness during the transmission phase of the knee joint can be explained by a combination of the pre-activity of the VL muscle and the knee joint angular velocity at touchdown (F = 5.76, P < 0.05). These results seem to emphasize the functional significance of the pre-programmed activity for controlling the subsequent stiffness regulation and then contributing to the performance in DJ. Thus, it can be suggested that the centrally pre-programmed activity and the associated elastic behavior of the SEC in the knee extensor muscle in conjunction with the muscle contractile property play a major role in regulating the performance in DJ.