Analysis of rapid stopping during human walking
Analysis of rapid stopping during human walking
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DOI：
10.1152/jn.1998.80.1.255
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发表时间：
1998-07-01
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
研究了快速终止人类步态的机制。受试者被要求以舒适的速度行走，并在感到腓浅神经受到电刺激时立即停止行走。这模拟了用脚背撞击障碍物。在 20 分钟的步行时间内随机重复出现刺激。记录右腿的肌电图和关节角运动以及双脚下的力。将步循环分为16个部分，并分别分析每个部分对刺激的反应。受试者通常会右脚停在左脚前面，反之亦然，具体取决于在步进周期中施加刺激的时间。还有一个过渡区域，受试者会踮起脚尖，然后退后一步，或者向前迈出更快、更短的一步。使用三种不同的机制来产生停止。 I) 摆动腿的伸展协同作用在该腿落地之前启动，以制动身体的向前动力。 2）禁止站立腿的推出阶段，以减少向前的推力并将站立腿保持在身体后方的地面上。 3）如果这些机制不够，身体会上升到向前延伸的腿的脚趾上，从而将更多的动能转化为势能。采取额外步骤的决定取决于身体的动量是否足以将质心带到前腿的支撑前方。如果是，则采取附加步骤。尽管必须做出的决定很复杂，但在 150-200 毫秒内可以看到整个腿部和躯干的肌电活动发生变化。
The mechanisms involved in rapidly terminating human gait were studied. Subjects were asked to walk at a comfortable speed and to stop walking as soon as they felt an electrical stimulus to the superficial peroneal nerve. This simulated hitting an obstacle with the top of the foot. Stimuli were presented repeatedly at random during a 20-min period of walking. Electromyograms and 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. Subjects generally stopped with the right foot in front of the left or vice-versa, depending on when the stimulus was applied in the step cycle. There was also a transition region in which subjects would rise up on their toes and either back down or take one more quick, short forward step. Three different mechanisms were used to produce a stop. I) An extension synergy in the swing leg was initiated just before this leg hit the ground to brake the forward momentum of the body. 2) The push-off phase of the stance leg was inhibited to reduce the forward thrust and maintain the stance leg on the ground behind the body. 3) If these mechanisms were insufficient, the body rose up onto the toes of the extended forward leg and thereby converted more kinetic energy to potential energy. A decision to take an additional step depends on whether the momentum of the body is sufficient to carry the center of mass in front of its support on the forward leg. If so, an additional step is taken. Despite the complexity of the decisions that must be made, changes in electromyographic activity are seen throughout the legs and trunk in 150-200 ms.