Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, D-3, DK-9220 Aalborg, Denmark.
J Electromyogr Kinesiol. 2010 Jun;20(3):457-64. doi: 10.1016/j.jelekin.2009.07.002. Epub 2009 Aug 13.
The study compared the distribution of electromyographic (EMG) signal amplitude in the upper trapezius muscle in 10 women with fibromyalgia and in 10 healthy women before and after experimentally-induced muscle pain. Surface EMG signals were recorded over the right upper trapezius muscle with a 10 x 5 grid of electrodes during 90 degrees shoulder abduction sustained for 60s. The control subjects repeated the abduction task following injections of isotonic and hypertonic (painful) saline into the upper trapezius muscle. The EMG amplitude was computed for each electrode pair and provided a topographical map of the distribution of muscle activity. The pain level rated by the patients at the beginning of the sustained contraction was 5.9+/-1.5. The peak pain intensity for the control group following the injection of hypertonic saline was 6.0+/-1.6. During the sustained contractions, the EMG amplitude increased relatively more in the cranial than caudal region of the upper trapezius muscle for the control subjects (shift in the distribution of EMG amplitude: 2.3+/-1.3mm; P<0.01). The patient group showed lower average EMG amplitude than the controls during the contraction (P<0.05) and did not show different changes in EMG amplitude between different regions of the upper trapezius. A similar behavior was observed for the control group following injection of hypertonic saline. The results indicate that muscle pain prevents the adaptation of upper trapezius activity during sustained contractions as observed in non-painful conditions, which may induce overuse of similar muscle compartments with fatigue.
这项研究比较了 10 名纤维肌痛女性和 10 名健康女性在实验性肌肉疼痛前后上斜方肌表面肌电（EMG）信号振幅的分布。在右斜方肌上使用 10x5 个电极网格记录表面 EMG 信号，在 90 度肩外展时持续 60 秒。对照组在向斜方肌上注射等渗和高渗（疼痛）盐水后重复外展任务。对每个电极对计算 EMG 幅度，并提供肌肉活动分布的地形图。患者在持续收缩开始时的疼痛评分为 5.9+/-1.5。对照组在注射高渗盐水后疼痛强度峰值为 6.0+/-1.6。在持续收缩期间，对照组斜方肌上部的颅侧比尾侧的 EMG 幅度增加相对更多（EMG 幅度分布的转移：2.3+/-1.3mm；P<0.01）。与对照组相比，患者组在收缩过程中的平均 EMG 幅度较低（P<0.05），并且斜方肌上部不同区域的 EMG 幅度没有显示出不同的变化。在对照组注射高渗盐水后也观察到类似的行为。结果表明，肌肉疼痛阻止了在上斜方肌在持续收缩期间的活动适应，就像在非疼痛条件下观察到的那样，这可能导致类似肌肉隔间的过度使用和疲劳。
