EMG responses to maintain stance during multidirectional surface translations
EMG responses to maintain stance during multidirectional surface translations
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DOI：
10.1152/jn.1998.80.4.1939
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发表时间：
1998-10-01
影响因子：
2.5
通讯作者：
Horak, FB
中科院分区：
文献类型：
--
作者：
Henry, SM;Fung, J;Horak, FB
为了表征多方向控制站立姿势下的肌肉协同组织，记录了7名健康受试者的11条小腿和躯干肌肉的肌电活动，这些肌肉在12个不同的随机呈现方向上进行水平表面平移。对每个扰动方向的肌肉反应的潜伏期和幅度进行量化。检查每块肌肉的调谐曲线，以将肌肉反应的幅度与表面平移的方向联系起来。小腿和大腿肌肉的反应潜伏期是恒定的，与干扰方向无关。相反，另一条大腿[阔筋膜张肌(TFL)]和两块躯干肌肉[腹直肌(RAB)和竖脊肌(ESP)]的潜伏期要么早，要么晚，这取决于干扰方向。这三块具有方向特定潜伏期的肌肉在姿势控制中可能扮演着不同的角色，既是作为原动力的，也可能是不同翻译方向的稳定器，这取决于招募的时间。大多数肌肉调节曲线都在一个象限内，有一个最活跃的方向，通常是对斜面平移的反应。两个躯干肌肉(RAB和ESP)和两个下肢肌肉(半膜肌和腓骨长肌)具有两极调谐曲线，有两个不同的最大活动方向，这表明这些肌肉作为不同协同作用的一部分，可以发挥不同的作用，这取决于平移方向。肌肉调节曲线倾向于对12个不同方向的扰动做出反应，分成三个区域之一。两块肌肉[股直肌(RFM)和股直肌(TFL)]对外侧表面平移的反应最活跃。剩下的肌肉聚集成两个对角区域中的一个。对角线区域对应于主动水平力向量响应的两个主要方向。两块肌肉(RFM和内收肌长肌)的最大活动方向与它们基于解剖方向预测的最大活动方向垂直。每个协同区的一些肌肉不是解剖学上的协同者，这表明肌肉的招募是一个复杂的中央组织。结果表明，无论是简单的反射机制，还是固定的肌肉协同组织，都不足以解释在这个姿势控制任务中观察到的肌肉激活模式。我们的结果与肌肉潜伏期的中枢调节模式和外周对肌肉大小的影响相一致。我们建议使用灵活的肌肉协同作用连续体，以任务依赖的方式进行修改，用于平衡站姿控制。
To characterize muscle synergy organization underlying multidirectional control of stance posture, electromyographic activity was recorded from 11 lower limb and trunk muscles of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. The latency and amplitude of muscle responses were quantified for each perturbation direction. Tuning curves for each muscle were examined to relate the amplitude of the muscle response to the direction of surface translation. The latencies of responses for the shank and thigh muscles were constant, regardless of perturbation direction. In contrast, the latencies for another thigh [ tensor fascia latae (TFL)] and two trunk muscles [rectus abdominis (RAB) and erector spinae (ESP)] were either early or late, depending on the perturbation direction. These three muscles with direction-specific latencies may play different roles in postural control as prime movers or as stabilizers for different translation directions, depending on the timing of recruitment. Most muscle tuning curves were within one quadrant, having one direction of maximal activity, generally in response to diagonal surface translations. Two trunk muscles (RAB and ESP) and two lower limb muscles (semimembranosus and peroneus longus) had bipolar tuning curves, with two different directions of maximal activity, suggesting that these muscle can play different roles as part of different synergies, depending on translation direction. Muscle tuning curves tended to group into one of three regions in response to 12 different directions of perturbations. Two muscles [rectus femoris (RFM) and TFL] were maximally active in response to lateral surface translations. The remaining muscles clustered into one of two diagonal regions. The diagonal regions corresponded to the two primary directions of active horizontal force vector responses. Two muscles (RFM and adductor longus) were maximally active orthogonal to their predicted direction of maximal activity based on anatomic orientation. Some of the muscles in each of the synergic regions were not anatomic synergists, suggesting a complex central organization for recruitment of muscles. The results suggest that neither a simple reflex mechanism nor a fixed muscle synergy organization is adequate to explain the muscle activation patterns observed in this postural control task. Our results are consistent with a centrally mediated pattern of muscle latencies combined with peripheral influence on muscle magnitude. We suggest that a flexible continuum of muscle synergies that are modifiable in a task-dependent manner be used for equilibrium control in stance.