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 Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, Montreal, Quebec H2W 1S4, Canada.
J Biomech. 2023 Jun;155:111638. doi: 10.1016/j.jbiomech.2023.111638. Epub 2023 May 16.
Females present more neck/shoulder musculoskeletal disorders and have different activation strategies of the shoulder girdle muscles than males. However, the sensorimotor performance and potential sex differences are still largely unexplored. The aim of this study was to investigate sex differences in torque steadiness and accuracy during isometric shoulder scaption. We also examined the amplitude and variability of the activation of the trapezius, serratus anterior (SA), and anterior deltoid muscles during torque output evaluation. Thirty-four asymptomatic adults (17 females) participated. Torque steadiness and accuracy were evaluated during submaximal contractions at 20 % and 35 % of peak torque (PT). There was no sex difference in torque coefficient of variation, but females had significantly lower torque standard deviation (SD) values than males at the two intensities evaluated (p < 0.001) and lower torque median frequency values compared to males, regardless of intensity (p < 0.01). Females had significantly lower absolute error values than males for torque output at 35 %PT (p < 0.01) and lower constant error values compared to males, regardless of intensity (p = 0.01). Females had significantly higher muscle amplitude values than males, except for SA (p = 0.10) and in general, females showed higher muscle activation SD values compared to males (p < 0.05). Females may require more complex muscle activation patterns to achieve a more stable and accurate torque output. Therefore, these sex differences may reflect control mechanisms that may also be at play when explaining the greater risk of neck/shoulder musculoskeletal disorders in females than males.
女性比男性更容易出现颈部/肩部肌肉骨骼疾病，并且肩部带肌肉的激活策略也不同。然而，传感器运动性能和潜在的性别差异在很大程度上仍未得到探索。本研究旨在调查等长肩抬高过程中力矩稳定性和准确性的性别差异。我们还检查了三角肌、前锯肌（SA）和前三角肌在力矩输出评估过程中的激活幅度和可变性。共有 34 名无症状成年人（17 名女性）参与了研究。在 20%和 35%峰值扭矩（PT）的亚最大收缩期间评估了力矩稳定性和准确性。在两个评估强度下，女性的力矩变异系数没有性别差异，但女性的力矩标准差（SD）值明显低于男性（p<0.001），且无论强度如何，女性的力矩中值频率值均低于男性（p<0.01）。女性在 35%PT 的力矩输出时的绝对误差值明显低于男性（p<0.01），且无论强度如何，女性的恒误差值均低于男性（p=0.01）。女性的肌肉幅度值明显高于男性，除了 SA（p=0.10），通常女性的肌肉激活 SD 值高于男性（p<0.05）。女性可能需要更复杂的肌肉激活模式来实现更稳定和准确的力矩输出。因此，这些性别差异可能反映了控制机制，这些机制在解释女性比男性更容易出现颈部/肩部肌肉骨骼疾病的风险时也可能发挥作用。
