Laboratory of Clinical and Occupational Kinesiology (LACO), Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, SP-310, São Carlos, São Paulo, Brazil.
Department of Occupational Health Sciences and Psychology, Centre for Musculoskeletal Research, University of Gävle, Kungsbäcksvägen 47, 801 76, Gävle, Sweden; Laboratory of Clinical and Occupational Kinesiology (LACO), Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, SP-310, São Carlos, São Paulo, Brazil.
Appl Ergon. 2020 May;85:103044. doi: 10.1016/j.apergo.2020.103044. Epub 2020 Jan 10.
The aim was to investigate if the method of normalizing surface electromyography (sEMG) can change results on sex differences in the muscular activation of the shoulder girdle muscles during a simulated work task. sEMG was recorded in 36 asymptomatic participants (17 females, 19 males) from four parts of trapezius and from serratus anterior muscles during a simulated work task. Four normalization methods, one involving maximal voluntary contractions (MVCs) and three involving submaximal voluntary contractions were applied. Sex differences in absolute and normalized amplitude of sEMG were analyzed. The normalization method had a significant influence on the observed sex differences. Females only showed higher sEMG amplitude than males when the sEMGs were normalized to MVC and to a submaximal contraction based on 20% of MVC for the upper trapezius (acromial fibers). Researchers and practitioners should be aware of the impact of the sEMG normalization method in sex differences investigation.
目的在于研究在模拟工作任务中，表面肌电图（sEMG）的归一化方法是否会改变肩带肌肉激活的性别差异结果。在模拟工作任务中，从斜方肌的四个部分和前锯肌记录了 36 名无症状参与者（17 名女性，19 名男性）的 sEMG。应用了四种归一化方法，其中一种涉及最大自主收缩（MVC），三种涉及亚最大自主收缩。分析了 sEMG 幅度的绝对和归一化性别差异。归一化方法对观察到的性别差异有显著影响。只有当 sEMG 被归一化为 MVC 以及上斜方肌（肩峰纤维）的 20% MVC 的亚最大收缩时，女性的 sEMG 幅度才高于男性。研究人员和从业者应该意识到 sEMG 归一化方法在性别差异研究中的影响。
