APAs和 CPAs是CNS在机体遭遇各种突发内部和外部姿势干扰条件下最早启动的姿势控制活动，在保持身体重心稳定、维系肢体空间定位和实现随意运动控制等方面发挥着重要的支撑和保障作用。以往研究发现，肌肉疲劳能够明显弱化肌肉收缩功能、CNS本体感受功能和运动控制功能等，造成身体重心稳定性破坏、肢体空间定位能力下降、关节失稳等现象，然而，肌肉疲劳对姿势控制的上述作用与CNS的早期控制机制有何关系，目前尚不完全清楚。本项目将在以往姿势控制理论研究的基础上，通过对局部肌肉疲劳与全身肌肉疲劳、主动肌疲劳与拮抗肌疲劳、单侧肢体肌肉疲劳与双侧肢体肌肉疲劳效应的实验观察，研究肌肉疲劳对踝关节、膝关节和躯干多关节姿势肌肉APAs和CPAs的作用，探讨肌肉疲劳影响CNS姿势稳定性控制的生理机制。

APAs and CPAs are the earliest postural adjustments initiated by the CNS in response to sudden self-induced or externally triggered posture perturbations. It has been shown that the performance of muscle contraction, the sensitivity of proprioception and the motor control from CNS were significantly decreased after muscle fatigue, which in turn affected the ability of maintaining limb orientation and the body stability. However, it's unclear whether those effects of muscle fatigue on postural control have any relationship with the early CNS activities on postural control. Aimed to investigate the physiological mechanism of muscle fatigue on postural control, the present grant proposal will simultaneously record the APAs and CPAs of the postural muscles during the following situations: local and global fatigue, agonist and antagonist fatigue, unilateral and bilateral fatigue. The key task is to figure out the effects of different kinds of muscle fatigue on the postural control and to explore its underlining mechanism.