Biological maturation selection biases across playing positions in youth football

An increasing number of studies reveal the influence biological maturation biases have on how coaches, clubs, and associations identify the players they want to develop. Do these biases affect the selection of players from all playing positions, or are some roles more impacted than others? The paper Dr Sweeney presents here attempts to answer this question with the help of a sample of male youth players competing at national and international levels for the Football Association of Ireland (FAI). Dr Sweeney co-authored this study with Dr Sean Cumming, Dr Áine MacNamara, and Dr Dan Horan.

• In Dr Sweeney’s sample of national and international male youth players, the influence of biological maturation selection biases differed between positions.  

• Although some positions did not exhibit selection biases in favour of early biological maturation, late-maturing players were still significantly under-represented across the total sample.   

• Club and coach education is necessary to raise awareness of the developmental impact biological maturation has on young football players.

Part 1: An overview of biological maturation in football
Children of the same chronological age can vary in their biological maturity by up to six years. This means that where one twelve year-old child might have the biological age of a 15-year old, another team-mate of the same chronological age might have the biological age of a nine-year-old. When it comes to football, children who mature earlier than their age-matched peers enjoy physical, functional and physiological advantages, such as being taller and heavier, having increased muscular strength and power, and having greater aerobic capacity compared to their later maturing team-mates. As a consequence, early-maturers are over-represented at many football academies from the age of 11-12 onwards – when puberty usually starts.

Part 2: Position-specific differences in biological maturation
After outlining the overarching topic of biological maturation, Dr Sweeney turns to the specific topic of the paper: the prevalence of biological maturation selection biases in different playing positions. Is there a bias towards selecting early developers across all playing positions, or does it vary? In Dr Sweeney’s sample of U-13 to U-16 national and international male youth players, biological maturation selection biases were largest in those positions most often involved in goal-scoring situations (goalkeepers, centre-backs and centre-forwards, wide-attacking midfielders). Although there were no selection biases in favour of early maturing players among central attacking midfielders and holding midfielders, late-maturing players were still significantly under-represented across the entire sample.

This under-representation of late developers across the sample as a whole serves to underscore the importance of this issue, and the need to raise awareness of it in talent identification. To round off his presentation, Dr Sweeney lays out other recommendations for how to address the prevalence of selection biases in youth academies, emphasising the importance of educating clubs and coaches about selection biases and the need for youth players to be routinely monitored so they can be provided with tailored, individual support.

Paper citation and link
Sweeney L, Cumming SP, MacNamara Á, Horan D. "The selection advantages associated with advanced biological maturation vary according to playing position in national-level youth soccer", Bio Sport, 2023; 40(3); pp715-722

Read the full paper here.