Department of Kinesiology and Physical Education, McGill University, Montreal, QC, H2W 1S4, Canada.
Occupational Biomechanics and Ergonomics Laboratory, Michael Feil and Ted Oberfeld/CRIR Research Centre, Jewish Rehabilitation Hospital, Laval, QC, H7V 1R2, Canada.
BMC Musculoskelet Disord. 2022 Jun 27;23(1):613. doi: 10.1186/s12891-022-05566-5.
Females are reported to have a higher risk of musculoskeletal disorders than males. Repetitive motions can lead to muscle fatigue, which may play a mediator role in the development of musculoskeletal disorders. However, sex differences in adaptations to localized fatigue at different joints are poorly understood. We examined the sex-specific effects of fatigue location on shoulder, elbow and spinal joint angles, and angular variabilities during a repetitive pointing task.
Seven males and ten females performed a 30-s standing repetitive pointing task with their right upper limb when they were non-fatigued (NF), elbow-fatigued (EF), shoulder-fatigued (SF) and trunk-fatigued (TF), while trunk and upper body tridimensional kinematic data was recorded. Joint angles and angular variabilities of shoulder, elbow, upper thoracic spine, lower thoracic spine, and lumbar spine were calculated.
Results showed that shoulder angles changed the most after EF in males, but after SF in females. The similarities between sexes were that SF increased the variabilities at upper (lateral flexion: 0.15° greater than NF, rotation: 0.26° greater than all other conditions) and lower thoracic spine (lateral flexion: 0.13° greater than NF, rotation: averagely 0.1° greater than all other condition) in both sexes. TF altered upper thoracic spine variability (0.36° smaller than SF), lower thoracic spine angle (lateral flexion: 3.00° greater than NF, rotation: 1.68° greater than SF), and lumbar angle (averagely 1.8° smaller than all other conditions) in both sexes. However, females had greater lower thoracic spine angle (lateral flexion: 8.3° greater, p = 0.005) as well as greater upper (rotation: 0.53° greater, p = 0.006) and lower thoracic spine (rotation: 0.5° greater, p = 0.007; flexion: 0.6° greater, p = 0.014) angular variabilities than males.
Results suggest that females' fatigue responses focused on the trunk and spine. Results highlight a few sex differences in adapting to localized muscle fatigue, which may help explain how sex differences in repetitive motion-related injuries differ between joints.
据报道，女性患肌肉骨骼疾病的风险高于男性。重复运动可导致肌肉疲劳，这可能在肌肉骨骼疾病的发展中起中介作用。然而，对于不同关节局部疲劳适应的性别差异知之甚少。我们研究了疲劳部位对肩部、肘部和脊柱关节角度以及重复性指向任务中角度变化性的性别特异性影响。
7 名男性和 10 名女性在非疲劳（NF）、肘部疲劳（EF）、肩部疲劳（SF）和躯干疲劳（TF）时使用右上肢进行 30 秒站立重复性指向任务，同时记录躯干和上半身三维运动学数据。计算肩部、肘部、上胸椎、下胸椎和腰椎的关节角度和角度变化性。
结果表明，男性在 EF 后肩部角度变化最大，而女性在 SF 后变化最大。男女之间的相似之处在于 SF 增加了上胸椎（侧屈：比 NF 大 0.15°，旋转：比所有其他条件大 0.26°）和下胸椎（侧屈：比 NF 大 0.13°，旋转：平均比所有其他条件大 0.1°）的变化性。TF 改变了上胸椎的可变性（比 SF 小 0.36°）、下胸椎角度（侧屈：比 NF 大 3.00°，旋转：比 SF 大 1.68°）和腰椎角度（平均比所有其他条件小 1.8°）。然而，女性的下胸椎角度更大（侧屈：大 8.3°，p=0.005），上胸椎（旋转：大 0.53°，p=0.006）和下胸椎（旋转：大 0.5°，p=0.007；屈曲：大 0.6°，p=0.014）的角度变化性也大于男性。
结果表明，女性的疲劳反应集中在躯干和脊柱。结果突出了一些性别差异在适应局部肌肉疲劳方面的差异，这可能有助于解释重复运动相关损伤在不同关节之间的性别差异。
