Balance and lower limb strength in young female athletes at different phases of the menstrual cycle: A causal-comparative descriptive study.

Fluctuations in female sex hormones throughout the menstrual cycle (MC) can affect the body's various metabolisms, leading to changes in physical performance parameters. This study examines lower limb strength and balance in the three phases of the MC in order to investigate the potential impact of the MC on athletic performance in female athletes. The study was conducted with 21 elite female athletes aged 20-25 y. The evaluations were performed during the early follicular (days 2-3), ovulation (days 13-14), and mid luteal (days 21-22) phases of MC. Subjects were subjected to the Y balance test (YBT), isokinetic strength test, single leg hop tests (SLHTs) (single hop for distance (SH), triple hop for distance (TH), crossover triple hop for distance (CH), medial side triple hop for distance (MSTH), and medial rotation (90°) hop for distance (MRH)) and dynamic/static balance tests. There was no statistically significant difference in lower extremity strength, strength asymmetries, or YBT test between sides and phases (p > 0.05). In isokinetic static balance, significance was observed in the mid-luteal phase in the forward-backward oscillation, while significance was observed in the medium-lateral speed in the ovulation phase (p < 0.05). In dynamic balance, the forward-backward oscillation of the trunk and the total oscillation were significant in the ovulation phase (p < 0.05). The MC phases had no effect on lower extremity strength, strength asymmetries, or YBT test; however, the lowest results in isokinetic balance tests were obtained in the ovulatory phase, while the highest results were obtained in the early follicular phase.