To estimate the contribution of chronological age, maturity status and body size as independent predictors of functional and sport-specific capacities adolescent basketball players. Stature, weight, functional capacity [countermovement vertical jump (power), 60-second sit-ups (abdominal strength-endurance), hand grip strength (static strength), 2-kg medicine ball throw (power), 20-m shuttle run (aerobic capacity)] and basketball-specific skills [passing, shooting, dribbling, defensive movements] were measured on 84 youth basketball players (13.0±0.6 years, 11.1–13.9 yrs). Stage of pubic hair (PH) was assessed at clinical examination. Multiple linear regression (backward method with the stepping criteria for removal of p<0.10) was used to estimate the relative contribution of age, stage of sexual maturity, height, weight and height x weight interaction to variation in functional and sport-specific capacities. Approximately 8% to 53% of the variance in functional capacities was accounted for by age, body size and maturity status: sit-ups, 8%, age, weight (p<0.05); vertical jump, 24%, maturity, height, weight (p<0.01); aerobic capacity, 39%, age, maturity, weight, height x weight interaction (p<0.01); medicine ball throw, 42%, height, weight (p<0.01); grip strength, 53%, age, height (p<0.01). In contrast, the predictors accounted for relatively little variance in sport-specific skills and maturity status was not a significant predictor: passing, 5%, weight (<0.05); time to complete defensive movements, 11%, height, weight (<0.01); dribbling, 18%, age, height, weight, height x weight interaction (<0.01); shooting, no significant predictors. With the exception of sit-ups, the predictors accounted for a greater proportion of variance in functional capacities than in sport-specific skills of adolescent basketball players.Table 1: Significant predictors of functional capacities in 13-to 14-year-old basketball players