Abstract
BACKGROUND/OBJECTIVES: Dribbling is a fundamental skill in soccer, but assessing the performance of youth players in this skill is complicated by the confounded effects of age and physical development. In this study, our aim was to quantify the interactive effects of age, height, and mass on the dribbling performance of 180 players between 10 and 21 years old from an elite Brazilian junior academy. METHODS: For each player, we quantified their dribbling and sprinting speed along four different paths with varying curvature, and their ability to perform specific, directed dribbling drills using one or both feet. To characterise patterns of variation among player's age, height, and mass-and to control for their confounding effects-we used a principal component analysis (PCA) to create a multivariate index of age and size (ASI). RESULTS: Dribbling, sprinting, and directed dribbling were all positively associated with ASI; however, age alone was a better predictor of performance than ASI. Using multi-model inference, we found that a player's overall dribbling was best predicted by models that included sprint speed and overall directed dribbling ability (p < 0.0001). When performing subsequent analyses that separate each of the directed dribbling drills into using dominant, non-dominant, or both feet, we found the best predictors of overall dribbling performance were sprinting and directed dribbling activities that use both feet. CONCLUSIONS: These results provide the first set of normative data for a detailed metric of dribbling performance and soccer-specific foot coordination that can allow players and coaches to compare and assess their performances relative to a single population of high-quality junior players.