Evaluation of a multidimensional physical performance test battery in young female volleyball players: Inter-trial reliability and principal component analysis

This study aimed to evaluate an integrated multidimensional physical performance test battery and explore its underlying structure in young female volleyball players. Forty-five female youth volleyball players aged 11–14 years (mean age 11.87 ± 0.97 years) completed a battery comprising bilateral handgrip strength, reaction distance, T-test agility, and Y-Balance assessments, together with vertical jump, core endurance, and sit-and-reach flexibility tests. Within-session inter-trial reliability was evaluated using the intraclass correlation coefficient (ICC(3,k)) and coefficient of variation. Performance variables were standardized using z-scores, and measures in which lower values indicated better performance were sign-inverted. Pearson correlations were used to examine bilateral relationships, and principal component analysis (PCA) with Varimax rotation was performed to explore the underlying performance dimensions. Age-group differences were examined using ANOVA or Kruskal–Wallis tests, as appropriate, with Bonferroni correction applied for multiple comparisons. A composite performance score was calculated as the unweighted mean of the six retained component scores. Handgrip strength, vertical jump, and Y-Balance performance demonstrated good-to-excellent within-session inter-trial reliability, whereas reaction distance showed moderate-to-good reliability with greater inter-trial variability. Bilateral measures were strongly correlated and consistently loaded on the same PCA components. Six components explained 81.27% of the total variance, representing agility with trunk extension and flexibility, handgrip strength, dynamic balance, core endurance, reaction distance, and vertical jump performance. After correction for multiple comparisons, significant age-group differences were observed only for right and left handgrip strength, whereas no significant differences were found among the PCA component scores or in the composite performance score. These findings provide preliminary support for a multidimensional approach to physical performance assessment and suggest that multiple complementary measures may help characterize individual performance profiles in young female volleyball players.