Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
Clinic Physical Medicine and Rehabilitation, Vestfold Hospital Trust, Stavern, Norway.
PLoS One. 2019 Mar 14;14(3):e0213778. doi: 10.1371/journal.pone.0213778. eCollection 2019.
The purpose of this study was to investigate muscle activity variability within and between the right and left side of lumbar muscles in patients with chronic low back pain (cLBP) compared to healthy controls (HCs) during sustained quiet sitting. Surface electromyographic (EMG) signals were collected bilaterally from the lumbar muscles with 2 high density surface EMG grids of 9x14 electrodes. Root mean square values (RMS) over 1-sec epochs of all bipolar EMG leadings were obtained. Between-sides alternating activation was computed, as well as temporal- and spatial variability within the electrode grids through the coefficient of variation and correlations between RMS distributions. The subjective influence of sitting was evaluated by the rating of perceived exertion and the amount of LBP on a numeric pain rating scale. Compared to HCs, the patients with cLBP had lower temporal (p = 0.03) and similar spatial muscle activity variability during sitting, despite a more variable sitting position. This did not result in increased muscle fatigue indicated by EMG, but the patients with cLBP reported higher levels of RPE during- and more LBP after the sitting and as a consequence ended the sitting earlier than HCs (p < 0.01). Present findings lend support to the presence of less tolerance for low-level static muscle load in patients with cLBP.
本研究旨在比较慢性下背痛（cLBP）患者与健康对照组（HCs）在持续安静坐姿下，腰椎肌肉左右两侧的肌肉活动变异性。使用 2 个 9x14 电极的高密度表面肌电图网格，双侧采集腰椎肌肉的表面肌电图（EMG）信号。获得所有双极 EMG 导联 1 秒时段的均方根值（RMS）。通过变异系数和 RMS 分布之间的相关性，计算双侧交替激活以及电极网格内的时变和空间变异性。通过感觉用力等级和数字疼痛评分量表上的下背痛程度来评估坐姿的主观影响。与 HCs 相比，尽管坐姿更可变，但 cLBP 患者在坐姿时的肌肉活动时变异性较低（p = 0.03），但空间变异性相似。这并没有导致 EMG 所指示的肌肉疲劳增加，但 cLBP 患者在坐姿期间和之后报告的 RPE 水平更高，并且因此比 HCs 更早结束坐姿（p < 0.01）。目前的研究结果支持 cLBP 患者对低水平静态肌肉负荷的耐受性较低。
