Motor programmes for the termination of gait in humans: organisation and velocity‐dependent adaptation
Motor programmes for the termination of gait in humans: organisation and velocity‐dependent adaptation
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人类终止步态的运动程序：组织和速度依赖性适应
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Y. Brenière
中科院分区：
文献类型：
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作者：
P. Crenna;Do Manh Cuong;Y. Brenière
1通过EMG，力板和运动记录，研究了负责搅动的肌肉活动的组织，其调制作为进展率和相关的机械效应的函数。对在脚后跟弹力瞬间提出的视觉提示的反应进行了定量分析，重点是代表性的腿和大腿肌肉，体重支撑（姿势）和振荡（秋千）肢体在三个不同的速度下进行的散步试验，在姿势肢体中，与刹车相关的EMG在停止信号后约150毫秒开始主要涉及后肌的序列（solus，sol和hamstring，HAM），但SOL显示出单个EMG爆发，EMG模式组成在拮抗肌肉中逐渐增加的成分。反应力以速度依赖性方式减少。平均而言，与扩展组（股四头肌，四头肌和索尔）的近端激活序列起着突出的作用。单个组件显示出密切的相关性，并且与姿势肢体始终平行地缩放时空参数。随着步行速度的提高。4结果表明，响应地面接触视觉提示的肌肉协同作用是由相对灵活的电动机命令根据重量调制的相对灵活的电动机命令而产生的。 - 肢体和单一的，相当强大的电动机程序在秋千上，机械限制与脚压力的相对位置和体重中心相关命令开始影响外力，可能会调节身体两侧之间的差异。
1 The organisation of the muscular activities responsible for the termination of gait, their modulation as a function of the rate of progression and the associated mechanical effects were investigated in normal adults, using EMG, force plate and kinematic recordings. In particular, the braking actions in reaction to a visual cue presented at the instant of heel‐strike were analysed quantitatively, with a focus on representative leg and thigh muscles of the weight‐supporting (stance) and oscillating (swing) limb, during walk‐and‐stop trials performed at three different velocities. 2 In the stance limb, the EMG associated with braking started approximately 150 ms after the stop signal and, on average, displayed a distal‐to‐proximal activation sequence that primarily involved the posterior muscle groups (soleus, SOL, and hamstring, HAM). With the exception of SOL, which showed a single EMG burst, EMG patterns consisted of two or three progressively larger components occurring reciprocally in antagonistic muscles. Increasing walking speed yielded a significant reduction of the activity in distal muscles, and a simultaneous increment in proximal muscles. The mechanical effect of the earlier braking actions, estimated from the backward‐directed wave of the horizontal ground reaction force, decreased in a velocity‐dependent manner. 3 In the swing limb the braking activities began approximately 330 ms after the stop signal and, on average, revealed a proximal‐to‐distal activation sequence with the extensor groups (quadriceps, QUAD, and SOL) playing a prominent role. They always consisted of single EMG bursts, largely co‐activated in the antagonist muscles. The onset latencies of the individual components showed a close correlation, and the spatio‐temporal parameters were always scaled in parallel. Unlike the stance limb, the mechanical braking action associated with the final contact of the swing limb increased with walking speed. 4 The results indicate that the muscle synergies responsible for the rapid termination of gait in response to a ground‐contact visual cue are produced by a relatively flexible set of motor commands modulated according to different velocity‐dependent strategies in the weight‐bearing limb, and by a single, fairly robust motor programme in the swing limb. Mechanical constraints related to the relative position of the centre of foot pressure and centre of body mass at the time the braking commands begin to affect external forces, may condition the difference between the two sides of the body.