High-density surface electromyography (HDEMG) is an electrophysiological technique that can be used to quantify the spatial distribution of activity within muscles. When pain-free individuals perform sustained or repetitive tasks, different regions within a muscle become progressively more active; this is thought to reflect a strategy to redistribute the load to different regions, thus limiting localised muscle fatigue. The use of HDEMG has revealed that when people with musculoskeletal pain perform the same tasks, the distribution of activity within the same muscle is usually different, and the same muscle region tends to be active throughout the whole task without progressive activation of different muscle regions. This potentially results in a focal overload of a muscle region, and may contribute to fatigue, localised muscle pain and potentially pain persistence and/or recurrence over time. Interestingly, not all patients with musculoskeletal pain present with this regional alteration in muscle activation, reflecting the heterogeneity of patient presentations. This article will briefly review the technique of HDEMG followed by a review of studies demonstrating spatial redistribution of muscle activity in asymptomatic people during both isometric and dynamic conditions, including functional tasks. Lastly, the article will provide a review of HDEMG studies with a focus on changes in the behaviour of the lumbar erector spine and upper trapezius in people with spinal pain. These studies have revealed subtle changes in the distribution of muscle activity in people with spinal pain, which may have relevance for onset, persistence or recurrence of symptoms and could become a target of novel therapeutic approaches.

中文翻译：

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高密度表面肌电图揭示了与疼痛相关的肌肉激活变化的新见解。

高密度表面肌电图（HDEMG）是一种电生理技术，可用于量化肌肉内活动的空间分布。当无痛个体执行持续性或重复性任务时，肌肉内的不同区域会变得越来越活跃。据认为，这反映了一种将负荷重新分配到不同区域的策略，从而限制了局部肌肉疲劳。HDEMG的使用表明，当肌肉骨骼疼痛的人执行相同的任务时，同一肌肉内的活动分布通常是不同的，并且在整个任务中同一肌肉区域倾向于活跃，而不会逐渐激活不同的肌肉区域。这可能会导致肌肉区域的局部超负荷，并可能导致疲劳，随着时间的流逝局部肌肉疼痛以及潜在的疼痛持续和/或复发。有趣的是，并非所有患有肌肉骨骼疼痛的患者均表现出这种区域性的肌肉激活改变，反映出患者表现的异质性。本文将简要回顾一下HDEMG的技术，然后再回顾一些研究，这些研究表明在等距和动态条件下（包括功能性任务）无症状人群中肌肉活动的空间再分布。最后，本文将对HDEMG研究进行回顾，重点研究脊柱疼痛患者的腰直立脊柱和上斜方肌的行为变化。这些研究表明，脊柱疼痛患者的肌肉活动分布有细微的变化，这可能与发作有关，