Veiersted K B
National Institute of Occupational Health, Oslo, Norway.
Eur J Appl Physiol Occup Physiol. 1991;62(2):91-8. doi: 10.1007/BF00626762.
The main purpose of this study was to evaluate the reproducibility of electromyographic (EMG) measurements and specifically to test a calibration procedure with submaximal test contractions. Bipolar surface electrodes (20 mm fixed distance) were repositioned by a tracing sheet on both trapezius muscles, halfway between acromion and processus prominens. Submaximal test contractions were performed by keeping both arms straight abducted 90 degrees and forward flexed 10 degrees for 15-s periods. The arm position could be precisely reproduced in the frontal plane, but deviated forwards by 4 degrees in the horizontal plane, where the sensitivity of the EMG response to arm position was lowest. The electrodes were repositioned within a radius of 3 mm with a probability of 90%. Large deviations in the EMG response were found within this radius and a significant depression of the EMG response was recorded over the middle part of the muscle (the innervation zone?). This change in sensitivity of the EMG response with electrode position occurred in parallel for the test and maximal contractions. The total coefficient of variation was estimated to be 23% for recurrent EMG measurements using the calibration procedure described.
本研究的主要目的是评估肌电图（EMG）测量的可重复性，特别是测试一种采用次最大测试收缩的校准程序。通过描图纸将双极表面电极（固定距离20毫米）重新放置在两侧斜方肌上，位于肩峰和隆突之间的中点。次最大测试收缩通过保持双臂伸直外展90度并向前屈曲10度，持续15秒来进行。手臂位置在额平面上可以精确重现，但在水平面上前倾4度，而在此平面上EMG反应对手臂位置的敏感性最低。电极在3毫米半径内重新定位的概率为90%。在此半径内发现EMG反应存在较大偏差，并且在肌肉中部（神经支配区？）记录到EMG反应显著降低。EMG反应敏感性随电极位置的这种变化在测试收缩和最大收缩中同时出现。使用所述校准程序进行重复性EMG测量时，总变异系数估计为23%。
