Assessing the influence of chronological and skeletal age on selection and physical performance in South African youth football

Abstract

This cross-sectional study examined potential selection-biases—specifically the Relative Age Effect (RAE) and maturation selection-bias—and explored how chronological age (CA) and skeletal age (SA) relate to physical performance in South African youth footballers. A total of 105 male players aged 10–18 years from two academies in the Western Cape province were assessed. Anthropometric data were collected, and SA was estimated using the BAUSport™ system. Performance outcomes included hip adduction and abduction strength (N), handgrip strength (kg), and standing broad jump (cm). Players were grouped into CA and SA percentile-bands across the full sample, and performance was compared using one-way Welch's ANOVA. Multiple linear regression was used to examine the predictive value of CA and SA on physical performance. RAE was evident, with more players born in the first half of the selection year. A key finding was the slightly delayed maturation profile in the sample, with an underrepresentation of early maturers—contrasting with trends that typically favour them. This suggests that RAE may have a stronger influence than early maturation on continued selection and participation. Both CA and SA were positively associated with performance, but SA emerged as the stronger predictor, particularly among younger players. However, performance differences plateaued at higher maturity levels. These findings highlight the influence of CA and SA on selection and performance in youth football. Considering maturity status into talent development strategies may promote more developmentally appropriate and equitable practices. The study provides important baseline data for future research in South African football.