Weight distribution influences the time required to lift the leg even under normal standing condition
Weight distribution influences the time required to lift the leg even under normal standing condition
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DOI：
10.1016/j.gaitpost.2009.01.005
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发表时间：
2009-06-01
期刊：
影响因子：
2.4
通讯作者：
Oda, Shingo
中科院分区：
文献类型：
--
作者：
Shinya, Masahiro;Yamada, Yousuke;Oda, Shingo
本研究的目的是证明无论初始姿势是自发控制还是通过视觉反馈控制，从安静的站立姿势开始单腿抬起任务所需的时间是否由初始重量分布（WD）决定。七个健康的年轻受试者进行了一个升降一条腿的任务，以响应由LED提供的视觉刺激。实验包括正常（N）条件，其中参与者双腿对称地站立，如主观估计的那样，以及三种反馈（FL，FC和FR）条件，其中参与者将WD调节为-20%（左加权为6：4）。0%（中心加权5：5）和20%（右加权4：6），分别通过使用视觉反馈。在N条件下，WD的试验间变异大于FC条件，这足以与抬腿所需的时间显著相关。WD和预期姿势调整持续时间之间的回归方程的斜率、截距和估计标准误在不同条件下是一致的。WD对预期姿势调整的影响的量化表明，所需的时间抬起腿被延迟2.81毫秒的质心移向升降腿由1毫米。我们的研究结果表明，不对称的负载是一个简单的生物力学因素，确定所需的时间启动随后的升降单腿任务。(C)2009爱思唯尔有限公司版权所有。
The purpose of the present Study is to demonstrate whether the time taken to initiate a lift-one-leg task from a quiet standing position is determined by the initial weight distribution (WD), irrespective of whether the initial posture is controlled spontaneously or by using visual feedback. Seven healthy young subjects performed a lift-one-leg task in response to visual stimulation provided by an LED. The experiment included the normal (N) condition in which the participants stand on both legs symmetrically, as subjectively estimated, and the three feedback (FL, FC and FR) conditions in which the participants regulate the WD at -20% (left-weighted by 6:4). 0% (center-weighted by 5:5) and 20% (right-weighted by 4:6), respectively, through the use of visual feedback. In the N condition, the intertrial variation of WD was larger than that of the FC condition, which was enough to significantly correlate with the time required to lift the leg. The slope, intercept, and standard error of estimation of the regression equation between the WD and the duration of anticipatory postural adjustment were consistent between conditions. The quantification of the effect of WD on anticipatory postural adjustment indicated that the time taken to lift the leg was delayed by 2.81 ms as the center of mass shifted toward the lifting leg by 1 mm. Our results demonstrate that asymmetric loading is a simple biomechanical factor that determines the time needed to initiate a subsequent lift-one-leg task. (C) 2009 Elsevier B.V. All rights reserved.