[4-min read]

Last month, we hosted a webinar on harnessing growth and maturation for youth development, featuring two leading voices in the field: Professor Sean Cumming (University of Bath) and Rob Mulcahy MSc, PhD (c) (Setanta College, former Head of Athletic Performance with Clare GAA). With over 140 participants, the session brought together coaches, practitioners, and researchers to explore how the latest science on growth and maturation can be applied to real-world youth development.

Professor Cumming is a world-leading researcher in growth and maturation, having worked with organisations like the Premier League and the Lawn Tennis Association. Rob Mulcahy, a PhD candidate and experienced practitioner, has implemented growth and maturation monitoring in a range of youth sport settings.

Below are the key takeaways from the session, including practical strategies and real-world examples. If you’d like to access a recording of the session, you can register for free at the link below.

1 / Biological Age Matters More Than Chronological Age

One of the central messages was the huge variation in biological maturity among children of the same chronological age. Professor Cumming illustrated this with striking examples from elite academies:

“Within some academies such as Manchester United, we’ve seen differences of five to six years in terms of biological age. Two boys, both nine years old, but one has a skeletal age of twelve, the other of six.”

Prof. Sean Cumming

This variation has major implications for talent identification, training design, injury prevention, and competitive equity. The current system, which groups by chronological age, often favours early developers and overlooks late bloomers.

2 / Early Developers Dominate, Late Developers Disappear

Data from both football and rugby academies show a strong selection bias towards early developers. By the time players reach U15 or U16, late developers are almost entirely absent from elite pathways.

“At Southampton’s Academy, early developers are three to four times overrepresented by the U15 and U16 age groups, while late developers are largely absent. In Scottish rugby, only 0.2% of academy players are late developers, compared to 15% in the general population.”

Prof. Sean Cumming

This bias can lead to talented late developers being released too early, as in the case of Rodri, who was cut from Atletico Madrid for being physically small, only to be bought back for €30 million after developing elsewhere.

3 / The Growth Spurt: A Critical Window for Injury Risk

Both speakers emphasised the increased risk of injury during periods of rapid growth, often referred to as “growing pains.” The data is clear: injury incidence peaks during the most rapid phases of the growth spurt, between 88-96% of predicted adult height.

“Injury risk rate pretty much follows a curve that is exactly the same as the adolescent growth spurt, with the peak amount of injuries being at the peak intensities of growth.”

Prof. Sean Cumming

Rob Mulcahy added that pre-PHV (Peak Height Velocity) athletes growing rapidly are at 4.4 times higher risk of injury. During phases of high growth, coaches should monitor growth rates and adapt training loads accordingly.

4 / Bio-Banding: Levelling the Playing Field

Bio-banding – grouping players by biological rather than chronological age – was highlighted as a powerful intervention. It challenges early developers to develop their technical ability, while giving late developers a fairer environment to showcase their abilities and take on leadership roles.

“When we do a bio-banded event, we restrict the variance to about 5% of predicted adult height. What we tend to find is a game with less emphasis on physicality and more on technical and tactical abilities.”

Prof. Sean Cumming

Rob Mulcahy shared practical examples from hurling, where a single age group could have a 5.2-year difference in biological age. Hurling coaches he worked with reported that bio-banding uncovered skill deficiencies in larger players and technical superiority in smaller ones, shifting their perceptions of talent.

5 / Practical Strategies for Coaches: Adapt, Monitor, and Educate

Rob Mulcahy outlined a three-stage approach to adapting training based on growth:

• Stage 1: Focus on flexibility as the feet grow.
• Stage 2: Emphasise technique as limbs lengthen.
• Stage 3: Address movement patterns as the torso grows.

He also described a “traffic light” system for monitoring athletes:

“Green means no issues, orange signals visual deficiencies, and red means pain – requiring intervention. Pain isn’t a sign that something’s happening; it’s an indication something has happened.”

Rob Mulcahy

Coach education is critical. Making growth and maturation concepts digestible for volunteer coaches helps ensure inclusive selection policies and better long-term athlete development.

6 / Long-Term Athlete Development: Training Should Evolve with Maturity

The speakers stressed the importance of aligning training content with the athlete’s stage of maturation:

• Pre-PHV: Emphasise fundamental movement skills and physical literacy.
• Mid-PHV: Focus on speed, agility, and strength, with careful load management.
• Post-PHV: Shift to structured strength and conditioning, hypertrophy, and tactical refinement.

Speed and skill development should also be tailored to each stage, with technical mastery prioritised before and during the growth spurt, and tactical/leadership skills developed post-PHV.

7 / Retention and Inclusion: Rethinking Success in Youth Sport

Finally, the speakers challenged the traditional focus on winning and early selection. Instead, they advocated for retention and inclusive practices:

“The GAA’s policy is as many as possible, for as long as possible, for as good as possible. Our focus is on retention and participation. If this information helps us keep more players, all the better.”

Rob Mulcahy

Changing the definition of success – from winning games to developing a quality curriculum and maximising participation – can help address the bias toward early developers and ensure more young athletes reach their potential.

Conclusion

Our webinar made it clear: understanding and applying the science of growth and maturation is essential for anyone working in youth sport. By recognising individual differences, adapting training, and challenging traditional selection practices, we can create safer, fairer, and more effective development environments for all young athletes.

If you missed the session, we encourage you to watch the recording and explore how these insights can be put into practice in your own setting.

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