Turning strategies during human walking
Turning strategies during human walking
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DOI：
10.1152/jn.1999.81.6.2914
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发表时间：
1999-06-01
影响因子：
2.5
通讯作者：
Stein, RB
中科院分区：
文献类型：
--
作者：
Hase, K;Stein, RB
研究了人类行走过程中快速转弯的机理。受试者被要求以舒适的速度行走，并在感觉到腓浅神经受到电刺激后立即转向指示的方向。在10到15分钟的步行时间里，随机重复呈现刺激，以向两个方向转弯。记录肌电图（emg）、右腿关节角运动和两足受力。将步进循环分为16个部分，分别分析每个部分对刺激的反应。根据哪条腿放在前面制动，使用了两种转弯策略。例如，当右脚放在前面时，要向右转，受试者通常通过绕右脚旋转身体来改变方向。在右脚前向左转时，受试者将重心移至右腿，向外旋转左髋，踩到左腿上，继续转身，直到右腿踩到新的方向（step turn）。步进式转身简单而稳定，因为在转身过程中支撑的基础比旋转式转身宽得多，所以有些人在整个循环过程中都使用步进式转身。最初，行走的减速类似于先前研究过的快速停止任务。减速机制涉及身体一侧肌肉（比目鱼肌、股二头肌和竖脊肌）从远端到近端的一系列激活。这种模式类似于“脚踝策略”，用于前倾时的姿势控制。挥拍腿脚的位置控制和立姿腿躯干旋转的肌肉活动发生在球杆后的一步之内。踝关节内翻器的作用和臀中肌活动引起的骨盆抬高可能有助于控制躯干旋转。这种活动与相反的脚撞击的时间密切相关，与施加刺激时的步进循环部分无关。在大多数受试者中，转弯是在没有重置基本步行节奏的情况下完成的。这是第一个快速转弯的肌电图分析，显示了姿势摇摆和停止的常见策略如何与两种转弯策略中的一种相结合。这简化了在步进循环中随机时间转弯的复杂任务。
The mechanisms involved in rapidly turning during human walking were studied. Subjects were asked to walk at a comfortable speed and to turn toward the instructed direction as soon as they felt an electrical stimulus to the superficial peroneal nerve. Stimuli were presented repeatedly at random over 10- to 15-min periods of walking for turning in both directions. Electromyograms (EMGs), joint angular movements of the right leg, and forces under both feet were recorded. The step cycle was divided into 16 parts, and the responses to stimuli in each part were analyzed separately. Two turning strategies were used, depending on which leg was placed in front for braking. For example, to turn to the right when the right foot was placed in front, subjects generally altered direction by spinning the body around the right foot (spin turn). To turn left when the right foot was in front, subjects shifted weight to the right leg, externally rotated the left hip, stepped onto the left leg, and continued turning until the right leg stepped in the new direction (step turn). The step turn is easy and stable because the base of support during the turn is much wider than in the spin turn, so some subjects used it in all parts of the cycle. Initially, the deceleration of walking is similar to a rapid stopping task, which has been previously examined. The deceleration mechanism involves a sequence of distal-to-proximal activation of muscles on one side of the body (soleus, biceps femoris, and erector spinae). This pattern is similar to the "ankle strategy" used in postural control during forward sway. The control of foot placement in the swing leg and muscle activities for rotating the trunk in the stance leg occurred within a step after the cue. The action of ankle inverters and elevation of the pelvis by activity of gluteus medius may contribute to the control of trunk rotation. This activity was closely related to the timing of the opposite foot strike, independent of the part of the step cycle when the stimulus was applied. In most subjects, the turn was completed without resetting the underlying walking rhythm. This first EMG analysis of rapid turning shows how common strategies for postural sway and stopping can be combined with one of two turning strategies. This simplifies the complex task of turning at a random time in the step cycle.