Canadian Centre for Rural and Agricultural Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Department of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
PeerJ. 2024 Jul 18;12:e17728. doi: 10.7717/peerj.17728. eCollection 2024.
The shoulder complex relies on scapular movement controlled by periscapular muscles for optimal arm function. However, minimal research has explored scapular muscle activation ratios during functional tasks, nor how they might be influenced by biological sex. This investigation aims to characterize how sex impacts scapular muscle activation ratios during functional tasks.
Twenty participants (ten females, ten males) were assessed with surface electromyography (EMG) and motion tracking during seven functional tasks. Activation ratios were calculated from normalized EMG for the three trapezius muscles and serratus anterior. Scapular angles were calculated using a YXZ Euler sequence. Two-way mixed methods ANOVAs ( < .05) were used to assess the effects of sex and humeral elevation level on ratios and angles.
Sex-based differences were present in the Tie Apron task, with males exhibiting higher upper trapezius/lower trapezius and upper trapezius/middle trapezius ratios than females. Males also demonstrated decreased internal rotation in this task. Other tasks showcased significant sex-based differences in scapular upward rotation but not in activation ratios. Humeral elevation generally demonstrated an inverse relationship with scapular muscle activation ratios.
This study highlights sex-based differences in scapular muscle activation ratios during specific functional tasks, emphasizing the need to consider sex in analyses of shoulder movements. Normative activation ratios for functional tasks were provided, offering a foundation for future comparisons with non-normative groups. Further research is warranted to confirm and explore additional influencing factors, advancing our understanding of shoulder activation and movement in diverse populations.
肩胛复合体依赖于肩胛带肌肉控制的肩胛骨运动，以实现最佳的手臂功能。然而，很少有研究探索过功能性任务中肩胛骨肌肉的激活比率，也不知道生物性别如何影响这些比率。本研究旨在探讨性别如何影响功能性任务中的肩胛骨肌肉激活比率。
20 名参与者（10 名女性，10 名男性）在进行 7 项功能任务时接受了表面肌电图（EMG）和运动跟踪评估。通过归一化 EMG 计算了三个斜方肌和前锯肌的激活比率。使用 YXZ Euler 序列计算肩胛骨角度。使用双向混合方法 ANOVA（<0.05）评估性别和肱骨抬高水平对比率和角度的影响。
在 Tie Apron 任务中存在基于性别的差异，男性的上斜方肌/下斜方肌和上斜方肌/中斜方肌比率高于女性。男性在这个任务中还表现出内旋减少。其他任务在肩胛骨上旋方面表现出显著的基于性别的差异，但在激活比率方面没有表现出差异。肱骨抬高通常与肩胛骨肌肉激活比率呈反比关系。
本研究强调了在特定功能性任务中肩胛骨肌肉激活比率的基于性别的差异，强调了在分析肩部运动时需要考虑性别。提供了功能性任务的正常激活比率，为未来与非正态群体进行比较提供了基础。需要进一步研究来确认和探索其他影响因素，以提高对不同人群肩部激活和运动的理解。
