Arm differences in muscle activity characteristics during a bilateral simulated overhead work in right-handed and ambidextrous individuals
Type de document
Études primaires
Année de publication
2025
Langue
Anglais
Titre de la revue
IISE Transactions on Occupational Ergonomics and Human Factors
Résumé
Background:
Many work tasks use both arms to execute in-phase bilateral movements above shoulders. However, bilateral limb asymmetries have been proposed to be a possible cause for injuries. Additionally, the dominant arm is more predisposed to musculoskeletal injuries. Should we assume that both arms’ exposure to injury risk factors is the same during a bilateral task, and is not impacted by handedness and sex? Purpose: We measured the effects of sex and fatigue on activity of bilateral shoulder muscle activity during a bilateral fatiguing overhead shoulder flexion task, among right-handed or ambidextrous individuals. Methods: Twenty-five healthy adults (13 males) completed a bilateral overhead fatiguing task with repetitive shoulder flexions from 90° to 135°. Exposure was measured using electromyographic data from six bilateral shoulder muscles, and their activation amplitude (RMS) and movement-to-movement variability (SD) were quantified. Data were analyzed separately for right-handed (n = 18) and ambidextrous (n = 6) males and females. One male participant was left-handed. Results: With fatigue, right-handed females had greater anterior deltoid activation in the dominant arm, whereas ambidextrous females showed increased activation of their right infraspinatus. All females had greater middle deltoid activation variability in the left arm compared to the right. In contrast, right-handed males had more middle deltoid activation amplitude and variability in their left arm, but otherwise had fewer arm differences. Conclusion: Our results indicate more impact of a bilateral fatiguing task on arm electromyographic asymmetries among females. Thus, job rotation such as alternating arms may pose a greater injury risk for females, since their shoulders show a clearer side dominance. Thus, to enhance human health and safety in a workplace, handedness and sex should be considered, and muscle activity measured, when implementing job/task rotation for exposure variation at work.
Mots-clés
Ergonomie, Ergonomics, Différence liée au sexe, Sex difference, Manutention manuelle, Manual handling
Numéro de projet IRSST
n/a
Citation recommandée
Renda, E., Liu, R. et Côté, J. N. (2025). Arm differences in muscle activity characteristics during a bilateral simulated overhead work in right-handed and ambidextrous individuals. IISE Transactions on Occupational Ergonomics and Human Factors. https://doi.org/10.1080/24725838.2025.2517026