Department of Mathematics and Computer Science, Università di Cagliari, Italy and Collegio Carlo Alberto, Turin, Italy.
Dept. of Electronics and Telecommunications, LISiN, Politecnico di Torino, Turin, Italy.
Sci Rep. 2024 Oct 3;14(1):22992. doi: 10.1038/s41598-024-69531-z.
Burst-like activation of postural muscles has been previously described and plays a crucial role in elucidating the strategies for postural control adopted by the central nervous system (CNS). A spatio-temporal descriptor of surface electromyographic (sEMG) bursts (STB) is proposed and applied to statistically quantify the burst-like activity of the right and left (R-L) lumbar erector spinae muscle of nine seated violinists playing for two hours. The STB signal is the number of pixels of the high density sEMG (HDsEMG) maps simultaneously showing sEMG amplitude above a given threshold. Burst activity was present in all nine subjects. Four of them met four stringent criteria allowing analysis of frequency, duration, and synchronization between the R-L bursts after 0, 15, 30, 60, 120 min of playing. Mean square coherence between STBs of the two muscles was > 0.75 within ⁓1 Hz bandwidth between 2.2 Hz and 4.5 Hz depending on subject. Non-parametric statistics was applied to compare, in time and space, the R-L features of the bursts. The mean STB width was significantly associated primarily to side and secondarily to time and ranged from 100 to 250 ms. The right STB signals led the left (p < 0.02) by 0 - 160 ms.The inverted pendulum composed by the upper body of a seated violinist is controlled in an intermittent way. The erector spinae of the selected subjects were active, on average, for less than 50% of the time. These findings demonstrate a CNS strategy of intermittent back muscle activation presumably aimed to reducing fatigue during hours of playing in seated violinists.
姿势肌肉的爆发式激活先前已被描述过，它在阐明中枢神经系统（CNS）所采用的姿势控制策略方面起着至关重要的作用。本文提出了一种表面肌电图（sEMG）爆发的时空描述符（STB），并将其应用于统计量化 9 名坐姿小提琴演奏者演奏两小时期间左右（R-L）竖脊肌的爆发式活动。STB 信号是高密度 sEMG（HDsEMG）图中同时显示高于给定阈值的 sEMG 幅度的像素数。在所有 9 名受试者中均存在爆发活动。其中 4 名受试者符合四项严格标准，允许在演奏 0、15、30、60、120 分钟后对 R-L 爆发的频率、持续时间和同步性进行分析。两种肌肉的 STB 之间的均方相干性在 2.2 Hz 至 4.5 Hz 的 ⁓1 Hz 带宽内为 ⁇ 0.75。应用非参数统计学来比较爆发在时间和空间上的 R-L 特征。平均 STB 宽度主要与侧别相关，其次与时间相关，范围从 100 到 250 ms。右侧 STB 信号比左侧（p < 0.02）提前 0-160 ms。坐姿小提琴演奏者的上身组成了一个倒立摆，以间歇性的方式进行控制。所选受试者的竖脊肌的活跃度平均不到 50%的时间。这些发现表明 CNS 采用了间歇性背部肌肉激活策略，可能旨在减少坐姿小提琴演奏者数小时演奏时的疲劳。
