久坐对脊椎肌肉sEMG信号的影响

采集18名女性受试者在不同久坐时间下，颈夹肌和竖脊肌在最大用力收缩（MVC）过程中的表面肌电（surface electromyography， sEMG）信号，分别考察其初始1.5 s的线性时频指标AEMG、MPF、非线性分析指标%DET的差异，以及全程MVC过程中MPF的变化趋势，以探讨久坐对脊椎肌肉活动水平和功能状态的影响.发现：在久坐前、久坐1.5 h、久坐3 h之后3种状态下，颈夹肌和竖脊肌在MVC的前1.5 s信号中，其时频信号AEMG、MPF及非线性信号%DET均无明显变化；在1 min脊椎持续MVC过程中，颈夹肌MPF均呈现线性递减趋势，且下降速率依次增大；竖脊肌MPF则呈现线性递增趋势，且上升速率依次减小.由此可得，久坐对于脊椎肌肉的最大收缩力量并无影响，但是对其维持最大收缩力量的能力有所改变.

The effect of sedentary on surface electromyographic activities of lumbar muscles

The aim of this study is to investigate the relation between sedentary and the variability of surface electromyography(sEMG) activity of lumbar muscles. Eighteen female participants performed three MVC tests(before testing,keep sitting 1.5 h and 3 h). sEMG signals were recorded from the left splenius cervicis and left erector spinae simultaneously. Results revealed that the linear indices AEMG, MPF and the non-linear indices %DET did not changed significantly in the first 1.5 s signals between the 3 MVC tests. The normalised MPF were all displayed declined linear tendency during the 1 min MVC tests for splenius cervicis, as while as the slope is steeper successively. On the contrary, for erector spinae, the normalised MPF were all displayed as inclined linear tendency during the three tests while the slope became to slow down. This study demonstrates that sedentary does not affect the MVC for spinal muscular strength, but it can change the maintenance of the MVC.