Vol. 7, Issue 2, Part D (2025)

Objective: This study tracked changes in multiple physical fitness indices among five female swimmers (aged 12-14) over the 2023-2024 period to evaluate trends in physical development. Methods: This employed a longitudinal research design featuring nine measurement sessions. The assessed indices included shoulder flexibility (cm), the sit-and-reach test, Counter Movement Jump height (CMJ, cm), sit-ups (reps) (40 pace/min), 3-Repetition Maximum (3-RM) for Squat and Bench Press, vital capacity (L), and times (s) for the 2,000 m mixed style and 3,000 m freestyle swimming tests. Data collection procedures for strength and conditioning followed the NSCA methodology. Statistical analysis utilized descriptive statistics, line charts, and the Friedman test (non-parametric repeated measures ANOVA). Results: Performance in the strength and conditioning tests (sit-ups, bench press, squat, vital capacity, sit-and-reach, CMJ) and specific swimming tests (2,000 m mixed style and 3,000 m freestyle) generally showed an upward trend across sessions, with shoulder flexibility markedly improving. Friedman tests revealed significant differences across measurement times for all variables (χ2≈32-40; p<0.001), accompanied by large effect sizes (Kendall’s W≈0.8-1.0). Wilcoxon comparisons between 2023 and 2024 indicated a slower rate of improvement in 2024; however, these differences were not statistically significant at the 0.05 level. Rapid gains occurred primarily early in 2023, followed by flatter curves suggesting the presence of plateaus. Conclusion: The two-year training program resulted in substantial improvements in muscular strength, flexibility, and endurance. The rate of improvement peaked in 2023 and decelerated in 2024, indicating potential plateaus and the necessity to adjust the current training regimen.