Preuss Richard, Fung Joyce
School of Physical and Occupational Therapy, McGill University, 3654 Promenade Sir William Osler, Montreal, Que., Canada H3G 1Y5.
J Electromyogr Kinesiol. 2008 Oct;18(5):815-28. doi: 10.1016/j.jelekin.2007.03.003. Epub 2007 Apr 20.
Surface perturbation has been used for decades to study balance and postural control; however the behavior of the trunk in these postural responses has been largely overlooked. Thirteen healthy males (18-23 yrs) were exposed to horizontal support surface translations delivered randomly in one of eight different horizontal directions in both sitting and standing. A 4-segment model of the trunk was used to estimate the kinematics and kinetics associated with the postural response, while surface EMG was acquired, bilaterally, from seven trunk muscles and one hip muscle. Multi-segmental movement was observed in the trunk in both test postures. Both the biomechanical and neuromuscular aspects of the trunk response were significantly affected by translation direction and test posture, with an interaction effect between these variables. The response in sitting was closely tied to the movement of the support surface, while the response in standing occurred in two phases: the first related to the dynamic response in the lower limbs, and the second tied to the movement of the support surface. As such, the observed postural responses could be largely explained by the biomechanical constraints of the system, such that the neural control of trunk equilibrium is simplified.
几十年来，表面扰动一直被用于研究平衡和姿势控制；然而，在这些姿势反应中，躯干的行为在很大程度上被忽视了。13名健康男性（18 - 23岁）在坐姿和站姿下，分别在八个不同水平方向中的一个方向上随机接受水平支撑面平移。使用一个四段式躯干模型来估计与姿势反应相关的运动学和动力学，同时双侧采集来自七块躯干肌肉和一块髋部肌肉的表面肌电图。在两种测试姿势下，躯干均观察到多节段运动。躯干反应的生物力学和神经肌肉方面均受到平移方向和测试姿势的显著影响，且这些变量之间存在交互作用。坐姿下的反应与支撑面的运动密切相关，而站姿下的反应分两个阶段：第一阶段与下肢的动态反应有关，第二阶段与支撑面的运动有关。因此，观察到的姿势反应在很大程度上可以由系统的生物力学约束来解释，从而简化了对躯干平衡的神经控制。
