Nagano Akinori, Komura Taku, Fukashiro Senshi
Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.
Biomed Eng Online. 2007 Jun 1;6:20. doi: 10.1186/1475-925X-6-20.
The purpose of this study was to investigate the coordination strategy of maximal-effort horizontal jumping in comparison with vertical jumping, using the methodology of computer simulation.
A skeletal model that has nine rigid body segments and twenty degrees of freedom was developed. Thirty-two Hill-type lower limb muscles were attached to the model. The excitation-contraction dynamics of the contractile element, the tissues around the joints to limit the joint range of motion, as well as the foot-ground interaction were implemented. Simulations were initiated from an identical standing posture for both motions. Optimal pattern of the activation input signal was searched through numerical optimization. For the horizontal jumping, the goal was to maximize the horizontal distance traveled by the body's center of mass. For the vertical jumping, the goal was to maximize the height reached by the body's center of mass.
As a result, it was found that the hip joint was utilized more vigorously in the horizontal jumping than in the vertical jumping. The muscles that have a function of joint flexion such as the m. iliopsoas, m. rectus femoris and m. tibialis anterior were activated to a greater level during the countermovement in the horizontal jumping with an effect of moving the body's center of mass in the forward direction. Muscular work was transferred to the mechanical energy of the body's center of mass more effectively in the horizontal jump, which resulted in a greater energy gain of the body's center of mass throughout the motion.
These differences in the optimal coordination strategy seem to be caused from the requirement that the body's center of mass needs to be located above the feet in a vertical jumping, whereas this requirement is not so strict in a horizontal jumping.
本研究旨在采用计算机模拟方法，研究最大努力水平跳跃与垂直跳跃相比的协调策略。
开发了一个具有九个刚体节段和二十个自由度的骨骼模型。三十二块希尔型下肢肌肉附着在该模型上。实现了收缩元件的兴奋 - 收缩动力学、限制关节运动范围的关节周围组织以及脚与地面的相互作用。两种运动均从相同的站立姿势开始进行模拟。通过数值优化搜索激活输入信号的最佳模式。对于水平跳跃，目标是使身体重心移动的水平距离最大化。对于垂直跳跃，目标是使身体重心达到的高度最大化。
结果发现，水平跳跃时髋关节的使用比垂直跳跃时更活跃。在水平跳跃的反向运动过程中，具有关节屈曲功能的肌肉，如髂腰肌、股直肌和胫骨前肌，被激活到更高水平，从而产生将身体重心向前移动的效果。在水平跳跃中，肌肉功更有效地转化为身体重心的机械能，这导致在整个运动过程中身体重心获得更大的能量增益。
最佳协调策略的这些差异似乎是由于垂直跳跃时身体重心需要位于双脚上方的要求，而水平跳跃时这一要求不那么严格所致。
