Menstrual Cycle Phases and Elite Female Soccer During Training: Exercise Load Perception and External Workload Monitoring

BACKGROUND: Female soccer has grown exponentially in the last years, however studies on women soccer players are very few compared with male ones and several inconsistencies are reported in the literature for female players. Physiological hormonal fluctuations during the different moments of menstrual cycle could have important implications on soccer performance, therefore, the aim of the present study was to investigate the impact of menstrual cycle phases on external and internal loads in elite women’ soccer players during an in-season training period, and to describe the internal-external training load relationship, in relation to different menstrual cycle moments. METHODS: 16 elite players from Italian soccer first division were monitored for 12 weeks. The main internal parameter (rate of perceived exertion - RPE), external variables (total time, total distance, high speed running - HSR, numbers of accelerations/decelerations) and session-RPE were collected during training sessions and analyzed trough a repeated-measures ANOVA to identify differences in the MC weeks. Menstrual cycle was monitored through daily questionnaires and was divided into four phases: menstruation week, pre-ovulation, post-ovulation, and pre-cycle. RESULTS: HSR and total distance were significantly lower during menstruation week than post-ovulation week (18318.70 ±1802.04 m vs 20358.41 ± 1639.27 m, respectively; p=0.022). A significant correlation was found in pre-cycle week between RPE and total distance (r=0.545; p=0.029), and between session-RPE with total distance (r=0.514; p=0.042) and total time (r=0.502; p=0.048). When considering the whole menstrual cycle, weak and moderate correlations were found for RPE and session-RPE with total time, total distance and HSR. CONCLUSION: Appropriate menstrual cycle monitoring is required for better interpretation of players’ response in elite women’s soccer training, given that during menstruation week, external load variables could be impaired. RPE and session-RPE values do not change statistically with changes in external variables, and their relationship showed unclear results, highlighting caution when interpreting them, and suggesting their use in combination with other parameters, especially during early follicular phase.