Physical performance and bioelectrical impedance vector analysis of female track and field athletes according to the follicular phase of the menstrual cycle

Purpose: The menstrual cycle (MC) and body composition are key biological variables in the study of female sports performance. This study aims to evaluate changes in body composition and performance during the follicular phase of the MC and verify any possible relationship between these changes. Methods: This cross-sectional study included 12 female track and field athletes (age 22.3 ± 2.6 years). Body composition was assessed using bioelectrical impedance vector analysis (BIVA), and physical performance was evaluated through tests of muscle flexibility, vertical and horizontal jump, speed, and endurance. Assessments were conducted during the early follicular phase (EF) and the late follicular phase (LF). Differences were analyzed using the paired sample t test, while Pearson’s correlation was applied to assess relationships between BIVA and performance variables across the EF and LF phases. Results: During the EF phase, standing long jump performance was reduced (2.36 ± 0.15 m vs. 2.40 ± 0.16 m; p < 0.03), and 400-m run times were slower (69.38 ± 5.68 s vs. 67.77 ± 6.22 s; p < 0.003) compared to the LF phase. No significant differences were observed in other performance parameters. No conclusive correlations were identified between BIVA values and physical performance across the EF and LF phases. Conclusion: Female athletes’ performance during the MC may be influenced by various factors. However, biological variables such as body composition likely offer only partial insights into these variations. A multidisciplinary and individualized approach is, therefore, recommended to optimize sports performance.