Sex Differences in Physiological Responses to a National Collegiate Athletic Association Division I Soccer Season

McFadden, BA, Walker, AJ, Cintineo, HP, Bozzini, BN, Sanders, DJ, Chandler, AJ, and Arent, SM. Sex differences in physiological responses to a National Collegiate Athletic Association Division I soccer season. J Strength Cond Res 38(11): 1891-1899, 2024-Identifying physiological changes that occur in response to workload demands can help to elucidate athlete management and recovery strategies. The purpose of this study was to compare the physical and physiological demands between men and women throughout the course of a collegiate soccer season. Men ( N = 23) and women ( N = 26) soccer players participated in blood draws before preseason (T1) and every 4 weeks thereafter (T2-T4). Workload was determined at all practices and games via heart rate and global positioning satellite monitoring systems. Repeated measures multivariate analysis of variance and linear mixed models were used to assess workload and biomarker responses throughout the season ( p < 0.05). Both teams experienced the highest workloads during the first 4 weeks of the season ( p < 0.05), which was followed by several biomarker perturbations. Sex-by-Time interactions were observed for total cortisol, growth hormone, insulin-like growth factor-1, thyroxine, thyroid-stimulating hormone, vitamin D, and omega 3 fatty acid index ( p < 0.05). Additional Sex effects were observed for free and total testosterone, estrogen, prolactin, sex-hormone binding globulin, creatine kinase, and iron levels ( p < 0.05). Women soccer players experienced further Time effects for free cortisol, iron, ferritin, and percent transferrin saturation ( p < 0.05). Male soccer players experienced additional Time effects for total testosterone, estrogen, creatine kinase, interleukin-6, triiodothyronine, and ferritin ( p < 0.05). Despite similar patterns of change in workloads, differential fluctuations in physiological markers were observed between the sexes. Understanding sex differences in response to comparable workloads may enhance exercise prescriptions for better athlete management plans. Additional strategies to increase iron may be warranted in female athletes.