Subject-Specific Muscle Synergies in Human Balance Control Are Consistent Across Different Biomechanical Contexts
Subject-Specific Muscle Synergies in Human Balance Control Are Consistent Across Different Biomechanical Contexts
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DOI：
10.1152/jn.00960.2009
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发表时间：
2010-06-01
影响因子：
2.5
通讯作者：
Ting, Lena H.
中科院分区：
文献类型：
--
作者：
Torres-Oviedo, Gelsy;Ting, Lena H.
身体的肌肉骨骼冗余为执行运动任务提供了多种解决方案。我们提出，神经系统通过招募运动模块或功能性肌肉协同作用来解决这个不受约束的问题，这些模块将运动意图映射到行动。与这一假设相一致，我们发现，在人类多向平衡控制的肌肉激活试验的变化受到一小部分肌肉协同作用的限制。然而，明显的肌肉协同结构可能会出现从扰动或低维最佳运动解决方案导致的感觉输入的特征模式。在这里，我们研究了在一系列生物力学背景下，平衡控制的肌电图（EMG）反应，这不仅改变了姿势扰动产生的感觉流入，而且还改变了用于恢复平衡的肌肉激活模式。在12个方向上的支持表面的翻译提供给受试者站在六个不同的姿势配置：单腿，窄，宽，非常宽，蹲下，和正常的立场。使用非负矩阵分解从每种条件中提取肌肉协同作用。此外，从正常的立场条件下的肌肉协同作用被用来重建肌肉激活模式在所有的立场条件。在各种条件下，每个受试者都招募了一组一致的肌肉协同作用。当平衡要求与正常姿势非常不同时（例如，单腿或蹲伏姿势），除了预先存在的肌肉协同作用之外，还招募了任务特定的肌肉协同作用，而不是产生从头肌肉协同作用。总之，我们的研究结果表明，肌肉协同作用代表一致的运动模块，映射意图的行动，无论生物力学的任务背景。
The musculoskeletal redundancy of the body provides multiple solutions for performing motor tasks. We have proposed that the nervous system solves this unconstrained problem through the recruitment of motor modules or functional muscle synergies that map motor intention to action. Consistent with this hypothesis, we showed that trial-by-trial variations in muscle activation for multidirectional balance control in humans were constrained by a small set of muscle synergies. However, apparent muscle synergy structures could arise from characteristic patterns of sensory input resulting from perturbations or from low-dimensional optimal motor solutions. Here we studied electromyographic (EMG) responses for balance control across a range of biomechanical contexts, which alter not only the sensory inflow generated by postural perturbations, but also the muscle activation patterns used to restore balance. Support-surface translations in 12 directions were delivered to subjects standing in six different postural configurations: one-leg, narrow, wide, very wide, crouched, and normal stance. Muscle synergies were extracted from each condition using nonnegative matrix factorization. In addition, muscle synergies from the normal stance condition were used to reconstruct muscle activation patterns across all stance conditions. A consistent set of muscle synergies were recruited by each subject across conditions. When balance demands were extremely different from the normal stance (e.g., one-legged or crouched stance), task-specific muscle synergies were recruited in addition to the preexisting ones, rather generating de novo muscle synergies. Taken together, our results suggest that muscle synergies represent consistent motor modules that map intention to action, regardless of the biomechanical context of the task.