Sex differences in whole-body neuromuscular patterns during a 2000 m rowing time trial

Previous research has shown that competitive female rowers are injured more often than males. However, no studies have examined sex differences in rowing performance outcomes and related neuromuscular manifestations across multiple body segments. Sixteen varsity rowers (9F/7M) completed a 2000 m time trial on a Concept 2 ergometer. A near-infrared spectroscopic (NIRS) probe on vastus lateralis (VL) measured muscle oxygenation. Electromyographic (EMG) surface electrodes were placed on 10 dominant-side muscles of the arm, trunk and leg. Both EMG and NIRS were analyzed at 7 distance intervals. Results show that females completed the time- trial in significantly more time than males. There was also a sex x distance interaction on heart rate, with earlier and more time-based fluctuations in females. Females also maintained a greater tissue oxygenation index during warm-up and until 1350 m (p < 0.001). Sex x distance interactions in activation amplitude were observed in rectus femoris, thoracic erector spinae, middle trapezius, and anterior deltoid. Activation amplitude in females generally decreased in across several upper body muscles while males generally maintained or increased. This study, for the first time, shows sex-specific neuromuscular adaptions during a 2000 m time trial. Understanding how males and females use their systems and whole-body muscles to row can help gain a better understanding of fatigue-mitigation strategies in this and other whole-body coordination tasks. Findings may help better understand how both sexes distribute muscular loads during whole-body maximal effort tasks and ultimately help prevent injury mechanisms for both sexes.