Age-related changes in countermovement jump performance and kinematics in young basketball athletes: a cross-sectional study

Background The purpose of this study is to investigate how jumping patterns evolve throughout the physical development of basketball players aged 13 to 16 years. Understanding these changes is crucial for performance evaluation and injury risk assessment in young athletes. Material and methods Jumping performance was assessed using video analysis and the OptoJump system during the Countermovement Jump (CMJ) test. Participants included male basketball players aged 13 to 16 years, categorised into age groups of 13, 14, 15, and 16 years. Key kinematic parameters were measured. Differences between adjacent age groups were assessed. Logistic regression analysis was conducted to identify significant factors contributing to jump performance. Results Results indicated that from ages 14 to 15, players exhibited a decrease in ankle dorsiflexion, likely due to ankle plantar flexor stiffness and imbalances in muscle-tendon development. By age 16, however, athletes began to display a more consolidated jumping pattern, characterised by increased ankle dorsiflexion and reduced trunk involvement. In contrast, younger players relied more heavily on trunk movement and limited ankle dorsiflexion, likely as compensatory mechanisms for insufficient lower limb power. Logistic regression confirmed that knee and ankle dorsiflexion, along with knee valgus, significantly contributed to jump performance. Conclusions This study highlights the importance of monitoring jumping kinematics in young basketball players to optimise performance and mitigate injury risks. Additionally, an interpretable machine learning model based on the Naive Bayes method was developed to predict jump performance in young athletes.