Abstract
BACKGROUND: Volleyball performance relies heavily on agility, strength, and the ability to change direction, yet there is limited research investigating these physical attributes across different age groups in youth volleyball players. The change of direction (COD) deficit-a metric that isolates directional efficiency by comparing agility to linear speed-may provide a more nuanced understanding of an athlete's movement capabilities. The aim of this study was to investigate: (i) the differences in anthropometrics, lower limb strength/power, dynamic balance, linear sprint speed, and change of direction (COD) ability between young volleyball age groups; (ii) the effect of age on COD deficit in young volleyball players, and; (iii) the COD deficit predictors. METHODS: A cross-sectional analysis of young volleyball athletes was conducted. Seventy-seven female volleyball players from three age groups (U13:12.43 ± 0.89; U16:14.38 ± 0.52; U18:16.78 ± 0.93) participated in standardized tests measuring their physical qualities. RESULTS: The older age groups (U18) were significantly taller, heavier, and faster in linear sprints than their younger counterparts. No significant differences between groups were observed in lower limb strength and power or dynamic balance. The U16 group demonstrated the lowest COD deficit. The regression analysis identified drop jump height (DJ) as the sole significant predictor of COD deficit, explaining 6.9% of the variance (R(2) = 0.069, p = 0.033), highlighting its relevance as an indicator of reactive strength. CONCLUSIONS: These findings suggest that while anthropometric features have increased and sprint performance improved with age, there is no corresponding improvement in lower limb strength, power, or dynamic balance. Drop jump height was the sole predictor of COD deficit, emphasizing the importance of reactive strength in determining agility. Coaches should focus on enhancing lower limb strength and reactive power to optimize COD performance and prevent performance stagnation (training plateaus), particularly in older athletes.