The effect of walking speed on muscle function and mechanical energetics
The effect of walking speed on muscle function and mechanical energetics
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DOI：
10.1016/j.gaitpost.2007.11.004
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发表时间：
2008-07-01
期刊：
影响因子：
2.4
通讯作者：
Kautz, Steven A.
中科院分区：
文献类型：
--
作者：
Neptune, Richard R.;Sasaki, Kotaro;Kautz, Steven A.
在大范围内调节速度在行走中很重要，但对神经运动模式如何适应不同速度变化的能量需求的理解还不是很清楚。这项研究的目的是利用肌肉驱动的正向动力学模拟来确定个体肌肉对以更快的稳态速度行走做出的功能和能量适应。关于肌肉是否对躯干支撑、向前推进或腿部摆动起作用，模拟数据不随速度变化。躯干支撑(垂直加速度)在站立早期主要由髋关节和膝关节伸肌提供，在站位晚期主要由足底屈肌提供，而躯干推进(水平加速度)在站立晚期主要由比目鱼肌和股直肌提供，这些肌肉的贡献都随着速度的增加而系统地增加。结果还强调了启动和控制腿部摆动的重要性，因为在较高的行走速度下，髂腰肌在摆动前和摆动早期加速腿部的肌肉工作显著增加，而双关节腿筋肌肉在摆动后期减速的工作增加。此外，与较快或较慢的速度相比，接近自选速度(1.2m/S)的步行提高了单关节踝关节足底屈肌的弹性能量存储和恢复的利用率，并减少了负纤维功。这些结果为了解步行中潜在的速度调节的神经运动机制提供了重要的见解，并为研究步行速度对病态人群中各种感兴趣的神经运动指标的影响提供了基础。(C)2007 Elsevier B.V.保留所有权利。
Modulating speed over a large range is important in walking, yet understanding how the neuromotor patterns adapt to the changing energetic demands of different speeds is not well understood. The purpose of this study was to identify functional and energetic adaptations in individual muscles in response to walking at faster steady-state speeds using muscle-actuated forward dynamics simulations. The simulation data were invariant with speed as to whether muscles contributed to trunk support, forward propulsion or leg swing. Trunk support (vertical acceleration) was provided primarily by the hip and knee extensors in early stance and the plantar flexors in late stance, while trunk propulsion (horizontal acceleration) was provided primarily by the soleus and rectus femoris in late stance, and these muscle contributions all systematically increased with speed. The results also highlighted the importance of initiating and controlling leg swing as there was a dramatic increase at the higher walking speeds in iliopsoas muscle work to accelerate the leg in pre- and early swing, and an increase in the biarticular hamstring muscle work to decelerate the leg in late swing. In addition, walking near self-selected speeds (1.2 m/s) improves the utilization of elastic energy storage and recovery in the uniarticular ankle plantar flexors and reduces negative fiber work, when compared to faster or slower speeds. These results provide important insight into the neuromotor mechanisms underlying speed regulation in walking and provide the foundation on which to investigate the influence of walking speed on various neuromotor measures of interest in pathological populations. (C) 2007 Elsevier B.V. All rights reserved.