Slobounov S M, Slobounova E S, Newell K M
a The Pennsylvania State University.
J Mot Behav. 1997 Sep;29(3):263-81. doi: 10.1080/00222899709600841.
This article is a report on 3 experiments designed so that the role of virtual time-to-collision (VTC), which specifies the spatiotemporal proximity of the center of pressure to the postural stability boundary in the regulation of posture in upright stances, could be examined. Virtual time-to-collision was estimated for normal upright stance with different bases of support, and for postural oscillations in which the speed of movement and instructional constraints on the coordination mode used were manipulated. The results showed that virtual time-to-collision was predictably reduced as (a) the base of support was reduced, (b) the speed of the postural oscillation was increased, and (c) the number of biomechanical degrees of freedom regulated in the coordination mode increased. Over a range of task conditions, the coefficients of variation of the VTC time-series were significantly lower than the coefficients of variation for the velocity and acceleration time-series of the center of pressure. The absolute values of VTC increased with the increment of the ground reaction forces a performer generated to avoid falling while approaching the stability boundary. These findings are consistent with the proposition that VTC may serve as an organizing informational control parameter for posture.
本文是关于3项实验的报告，这些实验的设计旨在探究虚拟碰撞时间（VTC）在直立姿势调节中所起的作用，VTC规定了压力中心与姿势稳定性边界的时空接近程度。针对不同支撑面的正常直立姿势以及对运动速度和所使用协调模式的指令约束进行了操控的姿势振荡，估算了虚拟碰撞时间。结果表明，随着以下情况虚拟碰撞时间会如预期般减少：（a）支撑面减小；（b）姿势振荡速度增加；（c）协调模式中受调节的生物力学自由度数量增加。在一系列任务条件下，VTC时间序列的变异系数显著低于压力中心速度和加速度时间序列的变异系数。当表演者在接近稳定性边界时为避免摔倒而产生的地面反作用力增加时，VTC的绝对值也会增加。这些发现与虚拟碰撞时间可能作为姿势的一种组织性信息控制参数这一观点相一致。
