The aim of this study was to evaluate if there are sex differences in postures of upper arm, upper back, head and neck after muscle fatigue induced by a simulated work task, requiring upper arm movements performed above shoulder level. Nineteen females and 18 males were evaluated. Upper arm elevation, upper back, head and neck forward flexion postures were recorded using digital inclinometers. The first and the last cycles of the task were considered as pre- and post-fatigue periods, respectively. For both periods, Amplitude Probability Distribution Function (APDF) was calculated for 10th, 50th and 90th percentiles, as well as the angular ranges between the 5th and 95th percentiles (APDF_5-95 range). The APDF_5-95 range for upper arm elevation was higher with fatigue, but with a higher increase for males. After fatigue, there was also a decrease in the upper arm elevation, with a larger decrease in males for the 10th and 50th percentiles. For head and neck, females showed higher APDF_5-95 ranges than males, regardless of the task period evaluated. After muscle fatigue, males adopted more neutral postures of the upper arm than females. Furthermore, females showed more non-neutral postures for head and neck. These findings suggest that the kinematic strategies adopted by females and males during a simulated work task are different and may predispose females to a higher risk of developing work-related musculoskeletal disorders of the neck.

这项研究的目的是评估在模拟工作任务引起的肌肉疲劳后，上臂，上背部，头和颈部的姿势是否存在性别差异，这需要上臂在肩膀上方进行运动。评价了19位女性和18位男性。使用数字测斜仪记录上臂抬高，上背部，头部和颈部的前屈姿势。任务的第一个和最后一个周期分别被认为是疲劳前后。对于两个周期，都分别计算了第10，第50和第90个百分位数的振幅概率分布函数（APDF），以及第5和第95个百分位数之间的角度范围（APDF _5-95范围）。APDF _5-95疲劳导致上臂抬高幅度增大，而男性则上升幅度更大。疲劳后，上臂的抬高也有所下降，在第10和第50个百分位数中，男性的下降幅度更大。对于头和颈部，无论评估的任务期如何，女性的APDF _5-95范围都比男性高。肌肉疲劳后，男性的上臂姿势要比女性的姿势更为中性。此外，女性表现出更多的头部和颈部非中性姿势。这些发现表明，男性和女性在模拟工作任务中采用的运动学策略是不同的，并且可能使女性更容易患上与工作相关的颈部肌肉骨骼疾病。