Staudenmann Didier, Taube Wolfgang
Movement and Sport Science, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland.
Movement and Sport Science, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland.
J Electromyogr Kinesiol. 2015 Apr;25(2):199-204. doi: 10.1016/j.jelekin.2014.11.003. Epub 2014 Nov 20.
The brachialis muscle (BR) represents an important elbow flexor and its activity has so far mainly been measured with intramuscular electromyography (EMG). The aim of this study was to examine whether the activity of the BR can be assessed with surface EMG without interference from the biceps brachii (BB). With eight subjects we measured surface EMG of the arm flexor synergists, BR, BB, and brachioradialis (BRR) during two isometric voluntary contraction types: (1) pure elbow flexion and (2) elbow flexion with a superimposed forearm supination. Since the BR and BB have a distinct biomechanical function, an individual activity of the BR can be expected for the second contraction type, if the BR can be assessed independently from the BB. The correlation coefficients between EMG amplitudes and flexion force (supination torque) were determined. During pure flexion the activities of all synergists were similarly correlated with the flexion force (r = 0.96 ± 0.02). During flexion+supination the activity of the BR was distinct from the activity of the BB, with a 14% higher correlation for the BR with the flexion force and a 40-64% lower correlation with the supination torque. The BB predicted supination torque substantially better than the BR and BRR (r = 0.93 ± 0.02). The current results demonstrate that the activity of the BR can be assessed with surface EMG as it was distinct from the BB during flexion+supination but predicted flexion force equally well as BB during the pure flexion contraction.
肱肌（BR）是重要的屈肘肌，迄今为止其活动主要通过肌内肌电图（EMG）进行测量。本研究的目的是检验能否通过表面肌电图评估肱肌的活动，且不受肱二头肌（BB）的干扰。我们让8名受试者在两种等长自主收缩类型中测量了手臂屈肌协同肌、肱肌、肱二头肌和肱桡肌（BRR）的表面肌电图：（1）单纯屈肘和（2）屈肘并叠加前臂旋后。由于肱肌和肱二头肌具有不同的生物力学功能，如果肱肌能够独立于肱二头肌进行评估，那么在第二种收缩类型中可以预期肱肌有单独的活动。测定了肌电图幅度与屈肘力（旋后扭矩）之间的相关系数。在单纯屈肘时，所有协同肌的活动与屈肘力的相关性相似（r = 0.96±0.02）。在屈肘+旋后时，肱肌的活动与肱二头肌的活动不同，肱肌与屈肘力的相关性高14%，与旋后扭矩的相关性低40 - 64%。肱二头肌预测旋后扭矩的能力明显优于肱肌和肱桡肌（r = 0.93±0.02）。当前结果表明，肱肌的活动可以通过表面肌电图进行评估，因为在屈肘+旋后时它与肱二头肌不同，但在单纯屈肘收缩时预测屈肘力的能力与肱二头肌相当。
