Developmental changes of vertical jump performance in young female basketball and volleyball players: A Bayesian multilevel modeling approach

Abstract

This study examined developmental trajectories of vertical jump performance in young female basketball and volleyball players using Bayesian multilevel modeling. Eighty-one Brazilian female athletes (basketball: n $=$ 46; volleyball: n $=$ 35) aged 11-18 years were assessed between 2016-2024 in a mixed longitudinal design. Models examined longitudinal age-related changes in countermovement jump performance, sport-specific differences, and body size effects. Results showed non-linear developmental patterns with accelerated improvement during early-to-mid adolescence followed by deceleration. Sport differences emerged in baseline performance levels rather than timing. Age effects strengthened after adjusting for body size ( ${\beta }^{\text{age}}$ $=$ 0.25, 68% credible interval [CI]: 0.17, 0.34; ${\beta }^{{\text{age}}^2}$ $=$ -0.18, 68% CI: -0.28, -0.08), indicating neuromuscular adaptations distinct from increases in body size. Body mass negatively associated with jump performance ( ${\beta }^{\text{body mass}}$ $=$ -0.35, 68% CI: -0.44, -0.25), while stature positively associated ( ${\beta }^{stature}$ $=$ 0.20, 68% CI: 0.10, 0.29). Volleyball players demonstrated lower baseline performance than basketball players ( ${\beta }^{volleyball}$ $=$ -0.35, 68% CI: -0.43, -0.27). Substantial between-athlete variability in baseline performance ( ${\sigma }_{intercept}$ $=$ 0.31) suggests limited predictive validity of early assessments. Our findings provide substantial female-specific evidence for developmental patterns in youth team sport athletes and demonstrate the utility of Bayesian methods for handling incomplete longitudinal data.