• The study, which was completed by the University of Bath, in collaboration with Edinburgh University, analyses the effect that relative age and biological maturation has on talent identification and development in the Club Academy Scotland (CAS) system

  • It highlighted that Scottish academies could be losing potential talent due to bias towards early maturing players.

  • In conjunction with this study, a new pilot rule has been introduced which allows clubs within CAS to group an increased number of players by biological maturity, giving late-developing players more time to flourish. 

  • As part of the next stage of the study, selected Scottish academies will investigate the growth-related injury incidence in CAS and its impact on players playing time.

  • Lack of education in the management of the growth spurt period was outlined as a key issue in youth development in the Scottish FA's Transition Report, which was published last year.

The world's biggest growth and maturation study in academy football has been commissioned by the Scottish FA, in a bid to aid early and late developers within Scottish football.

The report, which was completed by the University of Bath, in collaboration with Edinburgh University, analyses the impacts of relative age and biological maturation on talent identification and development within the Club Academy Scotland (CAS) system.

Completed between January and April 2024, the study involved over 1000 players - making it the largest sample size for research on combined relative age and biological maturity. Players' birth dates, current height and weight, and their parents' height and weight were recorded to predict their growth patterns and biological maturity.

It found that Scottish football followed the global trend of bias towards early developing players and the players born earlier in the year.

On the back of the findings from this study, a new pilot policy aimed at giving late-developing players more time to flourish has been introduced by the Scottish FA, with clubs within CAS given increased flexibility to group certain players by biological rather than chronological age. 

While academies will still use traditional age groups, they now have more flexibility to apply to the Scottish FA for dispensation to move certain players up and down age groups based on biological maturity – lifting the previous cap of three players. This flexibility allows the clubs to give players a more bespoke development plan that is suited to the players specific needs dependent on their stage of development. 

The findings of the study were presented to Scottish clubs at a Growth and Maturation Workshop held at Hampden Park.

Lack of education in the management of the growth spurt period was outlined as a key issue in youth development, in the Scottish FA's Transition Report. The importance of a Growth Maturation Strategy, helping both early and late-maturing players to excel, was also highlighted within the report's key recommendations.

Steve Curryn, Scottish FA PhD Researcher, who presented the research findings to the Scottish FA said: "Only 78% of boys matched their calendar age, while 7% were late developers and 15% were early developers.

"The largest biological age difference observed was six years, in the Under-15 cohort, with a boy aged 13.8 having a biological age of 12.3 and another aged 15 having a biological age of 18. However, the bias towards the early first appears at the Under-12 age group, before increasing in magnitude with each successive age group”.

“We found a significant selection bias towards early-maturing boys, especially by the Under-15 age group. Late developers, who should make up 15% of the population, were largely absent. We noticed trends of academies seemingly picking players based on size, strength, speed, and power rather than long-term potential.”

Mark Leslie, Sports Science & Data Manager at the Scottish FA, said: “The scale and quality of the research carried out allows us to answer questions on growth and maturation within our elite academies but also contribute to the global research community.

"We believe this pilot rule change can fundamentally change player development for the better. By allowing more opportunity for mixed-age playing based on biological maturity, all players, regardless of growth rate, can develop their skills and confidence.”

Lead researcher Professor Sean Cumming said: “Academies are often filled with early maturing players who’ve won the growth-spurt lottery. This rule will help level the playing field, giving late-developing players the chance to compete against peers at a similar stage, building their confidence and skills.

"Late developers make up around 15% of the general population, yet approximate only one to two per cent of academy footballers. Notable Scottish examples in football include Scott McTominay, Andy Robertson, and John McGinn, while players like Rodri and Kevin De Bruyne have also carved out successful professional football careers despite being late developers.

"But for every John McGinn, there’s many talented players are being overlooked because they are late developers. These players have to possess superior technical and psychological skills just to survive, but their abilities often get overshadowed by peers who use size and strength to dominate.

“This rule change will give clubs more opportunity to challenge early developers and help talented late developers build confidence by competing in a more suitable environment.”

This comprehensive study will also inform an upcoming review of youth development, conducted as part of the recommendations from the Transition Report, and will provide strong evidence and insights for future elite strategy development and player development programmes.

The Scottish FA also outlined the next step in the research, which will now look to understand and reduce the risk of injury during the growth spurt. Clubs have been asked to record their injuries alongside the growth and maturation data so that the association between the two can be assessed.