Stock Matt S, Thompson Brennan J
Muscular Assessment Laboratory, Texas Tech University, Lubbock, TX 79409, USA.
Physiol Meas. 2016 Mar;37(3):418-28. doi: 10.1088/0967-3334/37/3/418. Epub 2016 Feb 24.
During voluntary contractions in humans, the subcutaneous tissues between surface electrodes and active motor units have been shown to attenuate surface electromyographic (EMG) signal amplitude. The purpose of this investigation was to examine the relationship between adipose tissue thickness and the electromechnical delay (EMD) during maximal voluntary contractions (MVCs). Thirty-two healthy women (mean ± SD age = 21 ± 2 years; mass = 60.7 ± 11.5 kg; height = 161.7 ± 7.5 cm; dual-energy x-ray absorptiometry body-fat percentage = 33.1 ± 9.9%) performed MVCs of the right leg extensors while bipolar surface EMG signals were detected from the vastus lateralis muscle. EMD was calculated as the time (ms) between EMG and torque onsets. B-mode ultrasonography was used to determine adipose tissue thickness over the same location of the vastus lateralis where the EMG sensor was placed. Partial correlation was used to examine the relationship between adipose tissue thickness and EMD while statistically removing the influence of peak torque, EMG amplitude, and vastus lateralis muscle thickness. The partial correlation demonstrated no relationship between adipose tissue thickness and EMD (r = -0.010, p = 0.956). Collectively, these findings demonstrated that adiposity does not influence the estimation of EMD.
在人体自主收缩过程中，表面电极与活跃运动单位之间的皮下组织已被证明会衰减表面肌电图（EMG）信号幅度。本研究的目的是检查最大自主收缩（MVC）期间脂肪组织厚度与机电延迟（EMD）之间的关系。32名健康女性（平均±标准差年龄 = 21±2岁；体重 = 60.7±11.5 kg；身高 = 161.7±7.5 cm；双能X线吸收法测定体脂百分比 = 33.1±9.9%）进行右腿伸肌的MVC，同时从股外侧肌检测双极表面EMG信号。EMD计算为EMG与扭矩起始之间的时间（毫秒）。使用B型超声检查来确定放置EMG传感器的股外侧肌相同位置上的脂肪组织厚度。在统计上消除峰值扭矩、EMG幅度和股外侧肌厚度的影响的同时，使用偏相关来检查脂肪组织厚度与EMD之间的关系。偏相关表明脂肪组织厚度与EMD之间无关系（r = -0.010，p = 0.956）。总的来说，这些发现表明肥胖并不影响EMD的估计。
