Skeletal maturation status is a more powerful selection effect than birth quarter for elite youth academy football players

Introduction: Selection of younger athletes for advanced training in elite sport is assumed to be based on identification of innate talent. Previous researchers have identified relative age effects to influence these selection processes, however maturation status and relative skeletal age effects, which have the potential to be a greater influence, have not been widely examined. Methods: Skeletal Age (categorising athletes as: early maturing, on time, or late maturing via wrist and hand X-Ray and Fels classification) and Birth Quarter are documented for 472 boys from Elite Youth football Academies and compared to reference normative data to assess their effect on Academy selection. Results: Here we show that maturation status (categorising athletes as: early maturing, on time, or late maturing) is a much stronger influence – by an order of magnitude – on selection with a systematic over-representation of early maturing athletes in elite football academies; an effect that increases with age. Players born in the first and second quarters were over-represented across all age groups (U-9 to U-16), except under 17 where the RAE was not observed (p = 0.704). On the other hand, the skeletal age effect showed significant differences from the age category of U12 onwards compared to U9. This effect increased in magnitude with each successive age category (OR = 2.2, 95% CI (1.3–3.8) for the U-12 category and OR = 20.0, 95% CI (8.3–47.8) for U-17 Discussion: Our results demonstrate that athletes are being chosen in large by their maturation status, and as this relative benefit will have disappeared once all athletes are skeletally mature, this process is inadvertently excluding the majority of potential candidate athletes from this selection process. We suggest that consideration of maturation status of candidate athletes will result in a more equitable exposure to advanced training and the resultant performance benefits this incurs. Conversely, athletes who are currently being systematically excluded from such training by virtue of their maturations status will be more likely to continue within high performance streams of sports