Frère Julien
University of Lorraine, Laboratory "Development, Adaption and Disability" (EA 3450), Faculty of Sports Sciences, 30 rue du Jardin Botanique, CS 30156, F-54603 Villers-lès-Nancy, France.
Neuroscience. 2017 Jul 4;355:22-35. doi: 10.1016/j.neuroscience.2017.04.039. Epub 2017 May 5.
It is still unclear if muscle synergies reflect neural strategies or mirror the underlying mechanical constraints. Therefore, this study aimed to verify the consistency of muscle groupings between the synergies based on the linear envelope (LE) of muscle activities and those incorporating the time-frequency (TF) features of the electromyographic (EMG) signals. Twelve healthy participants performed six 20-m walking trials at a comfort and fast self-selected speed, while the activity of eleven lower limb muscles was recorded by means of surface EMG. Wavelet-transformed EMG was used to obtain the TF pattern and muscle synergies were extracted by non-negative matrix factorization. When five muscle synergies were extracted, both methods defined similar muscle groupings whatever the walking speed. When accounting the reconstruction level of the initial dataset, a new TF synergy emerged. This new synergy dissociated the activity of the rectus femoris from those of the vastii muscles (synergy #1) and from the one of the tensor fascia latae (synergy #5). Overall, extracting TF muscle synergies supports the neural origin of muscle synergies and provides an opportunity to distinguish between prescriptive and descriptive muscle synergies.
目前尚不清楚肌肉协同作用是反映神经策略还是反映潜在的机械约束。因此，本研究旨在验证基于肌肉活动线性包络（LE）的协同作用与纳入肌电图（EMG）信号时频（TF）特征的协同作用之间肌肉分组的一致性。12名健康参与者以舒适且自行选择的快速速度进行了6次20米步行试验，同时通过表面肌电图记录了11块下肢肌肉的活动。使用小波变换肌电图来获得TF模式，并通过非负矩阵分解提取肌肉协同作用。当提取出五种肌肉协同作用时，无论步行速度如何，两种方法都定义了相似的肌肉分组。考虑到初始数据集的重建水平时，出现了一种新的TF协同作用。这种新的协同作用将股直肌的活动与股四头肌的活动（协同作用#1）以及阔筋膜张肌的活动（协同作用#5）区分开来。总体而言，提取TF肌肉协同作用支持了肌肉协同作用的神经起源，并提供了区分规定性和描述性肌肉协同作用的机会。
