Resumen
The purpose of this study was to clarify the effect of body composition, particularly body fat percentage (BF%) and fat-free mass (FFM), on physical fitness and players? on-court performance in U-14 elite Portuguese basketball players. A total of 166 male basketball players (age, 13.80 ± 0.38 years) and 131 female basketball players (age, 13.57 ± 0.55 years) from under-14 (U-14) elite regional teams were evaluated. Differences between body composition groups, regarding physical tests and performance-related variables, adjusted for years at age peak velocity (YAPHV), were evaluated using ANCOVA tests, for male and female players. Results showed that: (i) low body fat male players jumped significantly higher and had more relative jumping power, were faster, and had better game performance than higher body fat male players, (ii) higher fat-free mass male players revealed significantly higher upper body strength and gained more rebounds than other players, (iii) higher body fat female players threw the medicinal ball further than other female players, and (iv) higher fat-free mass female players had significantly more upper body strength and jumped significantly lower than low fat-free mass female players. In conclusion, BF% seems to be oppositely associated with physical fitness and on-court performance in male basketball players, and FFM seems to be related to upper body strength in both sexes. Coaches should promote interventions that target lower BF% and ideal FFM mass values to improve physical and on-court performance in youth basketball.