Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan; Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan.
Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
J Biomech. 2021 May 7;120:110358. doi: 10.1016/j.jbiomech.2021.110358. Epub 2021 Mar 7.
Numerous muscles around the shoulder joint are required to work in a coordinated manner, even when a basic shoulder movement is executed. Muscle synergy can be utilized as an index to determine muscle coordination. The purpose of the present study was to investigate the muscle coordination among different shoulder muscles underlying basic shoulder movements based on muscle synergy. Thirteen men performed 14 multiplanar shoulder movements; five movements were associated with elevation and lowering, while five were associated with horizontal abduction and adduction. The four additional movements were simple rotations at different positions. Muscle activity was measured from 12 muscle portions using surface electromyography. Using the dimensionality reduction technique, synergies were extracted first for each movement separately ("separate" synergies), and then for the global dataset (containing all movements; "global" synergies). The least number that provided 90% of the variance accounted for was selected as the optimal number of synergies. For each subject, approximately two separate synergies and approximately six global synergies with small residual values were extracted from the separate and global electromyography datasets, respectively. Specific patterns of these muscle synergies in each task were observed during each movement. In the cross-validation method, six global synergies explained 88.0 ± 1.3% of the global dataset. These findings indicate that muscle activities underlying basic shoulder movements are expressed as six units, and these units could be proxies for shoulder muscle coordination.
在执行基本的肩部运动时，需要许多肩部关节周围的肌肉协调工作。肌肉协同作用可以作为确定肌肉协调性的指标。本研究的目的是基于肌肉协同作用，研究基本肩部运动中不同肩部肌肉的肌肉协调性。13 名男性进行了 14 项多平面肩部运动；5 项与抬高和降低有关，5 项与水平外展和内收有关。另外四项是在不同位置的简单旋转运动。使用表面肌电图测量了 12 个肌肉部分的肌肉活动。使用降维技术，首先为每个运动分别提取协同作用（“单独”协同作用），然后为全局数据集（包含所有运动；“全局”协同作用）提取协同作用。选择提供 90%方差的最小数量作为最佳协同作用数量。对于每个受试者，分别从单独和全局肌电图数据集中提取了大约两个单独的协同作用和约六个具有小残差值的全局协同作用。在每个任务中，都观察到了这些肌肉协同作用在每个运动中的特定模式。在交叉验证方法中，六个全局协同作用解释了 88.0±1.3%的全局数据集。这些发现表明，基本肩部运动的肌肉活动表现为六个单元，这些单元可以作为肩部肌肉协调性的代理。
