Powerlifting, including the bench press, has shown an increasing participation rate, especially among women. While rotator cuff injuries are prevalent in lifters, there is limited knowledge on how biological sex impacts shoulder biomechanics during the bench press. This study evaluated the impact of biological sex and fatigue on subacromial space parameters, specifically the acromiohumeral distance and supraspinatus occupation ratio, during the bench press. We hypothesized that the occupation ratio would be higher in female lifters than males. Twenty-four competitive powerlifters (12 M, 12 F) underwent ultrasound imaging to measure supraspinatus tendon thickness and acromiohumeral distance in seated and bench press postures across three phases: pre-warmup, post-warmup and post-exercise. The fatiguing exercise protocol consisted of three sets of eight bench press repetitions at 73.9% 1RM. Females exhibited higher supraspinatus occupation ratios than males in the bench press position (p = 0.001). Female lifters had a significantly smaller acromiohumeral distance than males in the bench press position (p < 0.001). The study found females have a greater supraspinatus occupation ratio during the bench press, increasing their risk for shoulder impingement compared to males. Understanding these sex differences in shoulder biomechanics during the bench press can guide tailored injury prevention and training strategies for powerlifters.
Motlagh et al. (Tue,) studied this question.