Developmental Differences in Morphological Predictors of Power, Change-of-Direction Speed, and Reactive Agility in Youth Male Basketball Players

Background: Morphological characteristics influence physical performance in youth basketball, but their effects may differ by developmental stage. This study compared the predictive role of morphological variables on motor performance between U13 and U15 male players. Methods: Male youth basketball players (N = 89) were assigned to U13 and U15 groups. Morphological variables included height, body mass, body fat percentage, and fat-free mass (FFM). Motor tests evaluated squat jump (SJ), countermovement jump (CMJ), 10 m and 20 m sprints, T-test, Y-test and Stop-and-Go change-of-direction speed and reactive agility (RA). Pearson correlations and multiple linear regressions assessed relationships and predictive effects. Results: In U13 players, several morphological variables correlated with performance: height and FFM were positively related to jumping and sprinting, while body fat was negatively associated with most measures (p < 0.05). Regression models explained substantial variance in sprint (ranging up to AdjR2 = 0.44) and jump performance (ranging up to AdjR2 = 0.32), though individual predictors were not always significant (p > 0.05). In U15 players, fewer associations emerged as body fat remained a significant negative predictor of jumping and agility, and greater body mass was associated with improved sprint performance (p < 0.05). No significant morphological predictors were found for RA in either group (p > 0.05). Conclusions: Morphological traits exert a stronger, multifactorial influence on performance in younger athletes, whereas body composition and particularly body fat are more influential in older adolescents. These results underscore the need to consider the developmental stage when assessing and training male youth basketball players.