This study investigated spatial distribution and asymmetry of surface electromyography on lumbar muscles during a sustained contraction in soldiers with and without chronic low back pain. Twenty healthy soldiers and twenty chronic low back pain (CLBP) soldiers had performed the Sorensen test with a duration of 60 seconds. The corresponding muscle fatigue, spatial distribution, and the asymmetry of muscle activity over bilateral paraspinal lumbar regions were measured by the high-density surface electromyography (HDsEMG). The paired and independent samples t-tests were performed to compare the degree of muscle fatigue and asymmetry. The repeated-measures analyses of variance (ANOVA) were used to compare spatial distribution between groups and muscle fatigue. The baseline characteristics of soldiers between groups were comparable. CLBP soldiers had significantly less muscle fatigue on both sides of erector spinae compared to healthy ones. The spatial distribution was significantly associated with the group factor but independent of muscle fatigue. In addition, the asymmetry of erector spinae activity in the CLBP soldiers was significantly higher than the healthy one. In conclusion, uneven spatial distribution and asymmetry of lumbar muscle activity play significant roles in CLBP patients. The HDsEMG could be used as an objective method in distinguishing the function of the erector spinae between healthy individuals and CLBP patients during 1 min sustained contraction.

中文翻译：

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慢性腰背痛士兵腰肌表面肌电图的空间分布和不对称性

这项研究调查了有无慢性腰痛的士兵持续收缩期间腰肌表面肌电图的空间分布和不对称性。20名健康士兵和20名慢性下腰痛（CLBP）士兵进行了60秒的Sorensen测试。通过高密度表面肌电图（HDsEMG）测量双侧脊柱旁腰区相应的肌肉疲劳，空间分布和肌肉活动的不对称性。成对的和独立样本吨-测试比较肌肉疲劳程度和不对称性。重复测量方差分析（ANOVA）用于比较组与肌肉疲劳之间的空间分布。各组之间士兵的基线特征具有可比性。与健康人相比，CLBP士兵的竖脊肌两侧肌肉疲劳明显减少。空间分布与组因子显着相关，但与肌肉疲劳无关。此外，CLBP士兵中竖脊肌活动的不对称性显着高于健康人。总之，CLBP患者的空间分布不均和腰肌活动不对称起着重要作用。