Acute effects of exercise-induced neuromuscular fatigue on postural control

控制姿势（或平衡）的能力是成功完成许多类型活动的先决条件。一场持续的运动，有时会导致疲劳，对姿势控制/平衡有重大影响。然而，并非所有类型的疲劳活动都会导致平衡障碍，并且可能受疲劳影响的平衡的具体控制特征/机制在很大程度上仍未被探索。***本研究计划的主要目的是确定中枢和外周疲劳对站立姿势的关键控制特征/机制的影响，以及这些影响是否根据所执行的姿势任务的性质/难度和研究人群而变化（未来的工作）。***实现这些目标的一般方法是首先描述并选择一组涉及不同程度的中枢和周围疲劳的疲劳练习/任务（提案的第1-2年）。然后，这组疲劳任务将用于提供受疲劳影响的特定（姿势）控制特征/机制的信息（3-5年）。这将通过对比反映不同疲劳任务之间平衡控制特征的变量的行为，以及不同难度的姿势任务之间的行为来实现，即：i)安静站立，ii)对离散姿势扰动的反应性反应，以及iii)对连续姿势扰动的反应性和预期性反应。在选定的导致疲劳的持续运动之前、期间和之后要评估的主要变量将包括力板（地面反作用力）的测量、身体部位位置和关节角度的测量以及肌肉活动。******意义***识别和理解影响姿势控制/平衡的因素对各个领域都很重要，包括康复科学（对正常运动控制的理解是设计干预措施以解决运动功能障碍的基础）、运动科学等。持续的运动有时会导致疲劳，这在日常生活中很常见，可能会干扰最佳的运动表现。然而，运动/疲劳对稳定性/平衡性控制的影响尚未得到系统的研究。因此，该项目将为控制站立姿势/平衡的重要因素提供有价值的新信息。

OBJECTIVES***The ability to control ones posture (or balance) is a prerequisite for the successful accomplishment of numerous types of activity. A bout of sustained exercise, sometimes leading to fatigue, can have a significant impact on postural control/balance. However, not all types of fatiguing activity lead to balance impairments, and the specific control features/mechanisms involved in balance that may be affected by fatigue remain largely unexplored. ***The main objectives of this proposed research program are to determine the effects of central and peripheral fatigue on key control features/mechanisms of standing posture, and whether these vary according to the nature/difficulty of the postural task performed and the population under study (future work).******APPROACH***The general approach used to address these objectives will be to first characterize and select a set of fatiguing exercises/tasks which will involve various levels of central and peripheral fatigue (years 1-2 of the proposal). This set of fatiguing tasks will then be used to provide information on the specific (postural) control features/mechanisms affected by fatigue (years 3-5). This will be achieved by contrasting the behavior of variables reflecting control features of balance between the different fatiguing tasks, but also between postural tasks of different levels of difficulty, namely: i) quiet standing, ii) reactive responses to discrete postural perturbations, and iii) reactive and anticipatory responses to continuous postural perturbations. The main variables of interest to be assessed before, during and after selected bouts of sustained exercise leading to fatigue will include measurements from force plates (ground reaction forces), measurements of body segments positions and joint angles, and muscle activity.******SIGNIFICANCE***The identification and understanding of factors affecting postural control/balance is important to various fields, including rehabilitation sciences (where the understanding of normal movement control is the basis for the design of interventions to address movement dysfunction), sports sciences, and others. Sustained exercise, sometimes leading to fatigue, is commonly experienced in everyday life and could interfere with optimal movement performance. However, the effect of exercise/fatigue on the control of stability/balance has not been studied systematically. This project will thus provide valuable novel information on factors important for the control of standing posture/balance.