Postural reactions of the trunk muscles to multi-directional perturbations in sitting
Postural reactions of the trunk muscles to multi-directional perturbations in sitting
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DOI：
10.1016/j.clinbiomech.2008.12.001
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发表时间：
2009-02-01
影响因子：
1.8
通讯作者：
Popovic, Milos R.
中科院分区：
文献类型：
--
作者：
Masani, Kei;Sin, Vivian W.;Popovic, Milos R.
背景：躯干肌肉系统在稳定性方面的动态作用迄今尚未得到充分研究。本研究的目的是，使用一个短暂的和多方向的扰动，以：（1）量化的紧张性活动水平在浅躯干肌肉组织之前的任何扰动;（2）量化的阶段性活动在这些相同的肌肉后的应用程序的一个短暂的，水平方向的负载;和（3）量化的方向依赖行为的这一阶段性反应。12名健康人在坐着期间通过胸部安全带在八个水平方向上受到干扰。从腹部（腹直肌，内，外肌）和背部肌肉组织（胸，腰竖脊肌）两侧测量表面肌电图，以确定紧张性肌肉活动扰动前，和扰动后的相位反应。一个描述性的模型被用来描述的相位之间的关系，由于扰动和拉direction.Findings的肌肉的反应：紧张性活动在躯干肌肉组织在直立坐着是低的，但仍然高于休息水平约1-3%的MVC的腹部肌肉，和4-6%的背部肌肉。每个躯干肌肉也表现出一个方向特异性，阶段性激活扰动响应，以上这些紧张性激活水平。使用每块肌肉的描述性模型对这种阶段性激活进行准确建模。释义：所获得的肌肉激活水平和所识别的描述性模型将应用于功能性电刺激的闭环控制器的设计中。(C)2008爱思唯尔有限公司保留所有权利。
Background: The dynamic role of the trunk musculature, with respect to stability, has not been fully explored to date. The purpose of this study was, using a transient and multi-directional perturbation, to: (1) quantify the tonic level of activity in the superficial trunk musculature prior to any perturbation; (2) quantify the phasic activity in those same muscles following application of a transient, horizontally directed load; and (3) quantify the direction-dependent behavior of this phasic response.Methods: Twelve healthy individuals were perturbed during sitting via a chest harness in eight horizontal directions. Surface electromyograms were measured bilaterally from the abdominal (rectus abdominis, internal and external obliques) and back musculature (thoracic and lumbar erector spinae) to determine the tonic muscle activity prior to perturbation, and the phasic response following perturbation. A descriptive model was used to characterize the relationship between the phasic response of the muscles due to perturbation and the pulling direction.Findings: Tonic activity in the trunk musculature in upright sitting is low, but still above resting levels by at about 1-3% of the MVC for the abdominal muscles, and 4-6% for the back muscles. Each trunk muscle also showed a direction-specific, phasic activation in response to perturbation, above these tonic levels of activation. This phasic activation was accurately modeled using a descriptive model for each muscle. Interpretation: The obtained muscle activation level and the identified descriptive model will be applied in the design of a closed-loop controller for functional electrical stimulation. (C) 2008 Elsevier Ltd. All rights reserved.