National Health and Medical Research Council Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, St. Lucia, Queensland 4072, Australia.
J Neurophysiol. 2010 Feb;103(2):968-76. doi: 10.1152/jn.00479.2009. Epub 2009 Dec 2.
Anticipatory postural adjustments (APAs) serve to stabilize posture prior to initiation of voluntary movement. This study examined the effects of changes in postural support on APAs using novel and familiar support paradigms. We also investigated whether postural strategies were refined with practice and how the CNS responded when multiple supports were available. Twelve healthy subjects stood on dual force platforms and performed 20 randomized left and right rapid leg-lift tasks in response to a visual cue under four conditions: unsupported, bilateral handgrip, bite plate, and a combined handgrip and bite plate condition. Vertical ground reaction forces, electromyography of limb, trunk and jaw muscles, and forces exerted on the support apparatus were recorded. Shift in center-of-pressure amplitude and duration were reduced with increased support. Muscles were recruited in advance of the focal movement when able to contribute to stability, and activity was modulated based on the amount of support available. The CNS adapted anticipatory postural strategies immediately with changes in condition regardless of familiarity with the support; however, adaptation was only complete at the first repetition in conditions that involved familiar support strategies. Tasks that involved a novel bite strategy continued to adapt with practice. In the multiple support condition, both hand and bite strategies were immediately incorporated; however, the contribution of each was not identical to conditions where supports were provided individually. This study emphasizes the flexibility of the CNS to organize postural strategies to meet the demands of postural stability in both familiar and novel situations.
预期姿势调整（APAs）用于在开始自愿运动之前稳定姿势。本研究使用新的和熟悉的支持范式研究了姿势支持变化对 APAs 的影响。我们还研究了姿势策略是否随着练习而得到改进，以及当有多个支撑时中枢神经系统如何做出反应。12 名健康受试者站在双力平台上，在四种情况下根据视觉提示进行 20 次随机的左右快速抬腿任务：无支撑、双手握持、咬板和双手握持加咬板。记录垂直地面反作用力、肢体、躯干和颌部肌肉的肌电图以及支撑装置上的力。随着支撑的增加，中心压力幅度和持续时间的变化减小。当能够有助于稳定性时，肌肉在焦点运动之前被募集，并且根据可用的支撑量来调节活动。中枢神经系统会立即根据条件的变化调整预期的姿势策略，无论对支撑的熟悉程度如何；然而，在涉及熟悉的支撑策略的条件下，只有在第一次重复时才会完全适应。涉及新的咬合力策略的任务随着练习而继续适应。在多支撑条件下，手和咬合力策略立即被整合；然而，它们的贡献与单独提供支撑时并不相同。本研究强调了中枢神经系统组织姿势策略的灵活性，以满足在熟悉和新情况下的姿势稳定性的要求。
