Gender Differences in the Relationship Between Fatigue, Different Types of Physical Activity, Postural Changes, and Sleep Quality in University Students—Part II Analyses from a Cross-Sectional Study

<b>Background:</b> Fatigue can be a useful tool to understand the effects of physical activity (PA) and sedentary behavior on musculoskeletal health in university students. <b>Methods:</b> The aim of this cross-sectional study was to examine gender differences in the relationships between fatigue and specific types and levels of PA, posture, sleep quality (SQ), and non-specific low back pain (NS-LBP) in young adult university students aged 18-25 years. A total of 180 students completed all required tests. <b>Results:</b> Female students had higher total fatigue as they generally engaged in more PA in contrast to male students, who had higher total fatigue when they engaged in less moderate and less vigorous PA. With increasing sedentary behavior, overall fatigue was pronounced in both sexes, although female students spent significantly more time sitting. Poorer SQ correlated with NS-LBP and higher levels of sleep-related fatigue in female students. Males with pronounced hypekyphosis and females with pronounced lordosis were more fatigued. In addition, fatigue was more pronounced in female students with a higher extensor/flexor ratio, suggesting that trunk extensors are more fatigued due to the need to maintain lumbar spine stability. <b>Conclusions:</b> Our findings suggest that the choice of PA should be gender-specific to prevent chronic musculoskeletal disorders and fatigue in young adult university students.