Domen K, Latash M L, Zatsiorsky V M
Department of Kinesiology, Pennsylvania State University, University Park 16802, USA.
Biol Cybern. 1999 Mar;80(3):195-204. doi: 10.1007/s004220050517.
The framework of the equilibrium-point hypothesis was used to reconstruct equilibrium trajectories (ETs) of the ankle, hip and body center of mass during quick voluntary hip flexions ('Japanese courtesy bow') by standing subjects. Different spring loads applied to the subject's back were used to introduce smooth perturbations that are necessary to reconstruct ETs based on a series of trials at the same task. Time patterns of muscle torques were calculated using inverse dynamics techniques. A second-order linear model was employed to calculate the instantaneous position of the spring-like joint or center of mass characteristic at different times during the movement. ETs of the joints and of the center of mass had significantly different shapes from the actual trajectories. Integral measures of electromyographic bursts of activity in postural muscles demonstrated a relation to muscle length corresponding to the equilibrium-point hypothesis.
平衡点假说的框架被用于重建站立受试者在快速自主髋关节屈曲（“日本礼节性鞠躬”）过程中踝关节、髋关节和身体质心的平衡轨迹（ETs）。通过对受试者背部施加不同的弹簧负荷，引入平滑扰动，这对于基于同一任务的一系列试验来重建ETs是必要的。使用逆动力学技术计算肌肉扭矩的时间模式。采用二阶线性模型来计算运动过程中不同时刻类似弹簧的关节或质心特征的瞬时位置。关节和质心的ETs与实际轨迹的形状有显著差异。姿势肌肉中肌电活动爆发的积分测量结果表明与平衡点假说对应的肌肉长度存在关联。
