Understanding Growth and Maturation in Youth Athletes: A Practical Guide
- Jo Clubb
- Aug 20
- 6 min read
Understanding growth and maturation in youth athletes is essential to monitor physical development, reduce injury risk, and design training that matches their biological age.
This post is based on my new Sports Science Insights video, supported by Action Apps, where I discussed the importance of monitoring growth and maturation in youth athletes, the science behind it, and how these measures can be applied in practice.
Growth and maturation status can vary widely between athletes of the same chronological age. These differences have major implications for talent identification, athletic development, and injury risk. By understanding and tracking this variability, practitioners can make more informed decisions that support both performance and long-term athlete development.
Growth, Maturation, and Development: Key Terms
It’s useful to clarify three terms that are often used interchangeably but have distinct meanings:
Growth is the physical increase in body size or specific body parts.
Maturation is the progression toward a biologically mature state.
Development is the broader process of acquiring skills, behaviours, and physical qualities across childhood and adolescence.
While we might expect maturation to progress in line with age, research has shown that it varies considerably between individuals. Differences exist in:
Timing – when maturation occurs
Tempo – how quickly maturation progresses
This means that an athlete’s chronological age (based on date of birth) may not align with their biological age (based on maturity status).
Peak Height Velocity (PHV): What It Is and Why It Matters
In a typical under-13 football team, athletes might share the same age category but vary greatly in maturity status. Importantly, height alone is not a reliable indicator. A taller athlete may be an early maturer, or simply destined to be tall while still maturing later than peers.
To understand maturity status, practitioners can track changes in height over time and plot height velocity curves, which show the rate of growth.
A critical marker of maturation is Peak Height Velocity (PHV): the period when adolescents grow in stature at their fastest rate.
On average:
Girls reach PHV around 11–12 years but it can occur anywhere from 9-15 years.
Boys reach PHV around 13–15 years but it can occur anywhere from 12-16 years.
These ranges illustrate the wide variability in growth timing. In addition, there is variation in the growth tempo. During PHV, athletes may grow anywhere between 5 and 12 cm per year, leading to rapid changes in body proportions and movement mechanics.
Therefore, at any one time, athletes in the same chronological age group may differ by up to six years in biological age. This has implications for physical performance and development, as well as talent identification and selection as we'll discuss next.
Why Maturity Status Matters
The rate and timing of physical growth and maturation profoundly shape their development, performance, and risk of injury. Let's consider the implications across talent identification, athletic development, and injury prevention.
Talent Identification
Youth sport often groups players by chronological age, which can favour early maturers. Research by Amanda Johnson et al in Science and Medicine in Football (2017) shows that academy selection processes tend to over-represent early maturers and under-represent late maturers. This bias risks overlooking talented athletes who simply develop later.
Bio-banding - grouping athletes by biological rather than chronological age - has emerged as one way to address this issue, with much of the research led by Sean Cumming.
Athletic Development
PHV is often accompanied by changes in coordination and movement strategies. James Baker’s et al systematic review (2025) found large differences in sprinting and jumping performance between pre- and post-PHV athletes.
During PHV, athletes may:
Experience decreased coordination
Show changes in movement strategy
Temporarily underperform in physical testing
Recognising these factors helps avoid misjudging an athlete’s long-term potential based on temporary performance dips caused by the maturation process.
Injury Risk
Rapid growth has been linked to increased injury risk, particularly growth-related conditions such as Osgood-Schlatter disease and Sever's disease (Monasterio et al., 2024).
Research by David Johnson and colleagues (2023) highlighted three key risk factors:
Maturity status – Being in the PHV window (generally, 88–92% of predicted adult height)
Growth tempo – Growing faster than ~7.2 cm/year
Lower limb growth rate – Strongly correlated with overall growth tempo
Injury risk during this phase can be mitigated by adjusting training loads, modifying strength programmes, and closely monitoring growth. It is worth noting however, that the vast majority of this research has been carried out on boys and more needs to be understood about maturation in girls.
Assessing Maturation Status
Measuring biological maturation directly (e.g. through skeletal X-rays or clinical assessment) is rarely feasible in sport settings. Instead, practitioners rely on indirect methods, such as somatic assessments.
Two common non-invasive methods are:
Maturity Offset – Based on the Mirwald equation (Mirwald et al., 2002 and subsequent variations), estimating years from PHV using chronological age, standing height, seated height, and body mass.
Khamis–Roche Method – Expresses current height as a percentage of predicted adult height using chronological age, height, body mass, and parental height.
This method is simple, non-invasive, and practical for field settings. However, its accuracy declines the further an athlete is from PHV and can vary between populations.
These approaches have limitations and inherent error. Generally, there are used in conjunction with each other, as you can see demonstrated in the Action Apps maturation dashboards in the video below. Ideally, this information is used together alongside other objective measures and subjective observations from coaches and support staff.
Action Apps Maturation Dashboards
The Action Apps maturation dashboards bring these concepts to life. As I demonstrate in the video above, key features include:
Visualising the disparity between chronological and biological age
Identifying athletes approaching PHV
Tracking growth tempo and predicted adult height
Highlighting those at higher injury risk based on research findings
We can see (even with this dummy data) how we might manage youth athletes differently based on the maturity status visualised in these reports. As I discuss in the demo, Liam Sanchez and Miles Freeman, for instance, are in distinctly different stages of maturation.
Dashboards can be customised in Power BI to suit the needs of your sport or organisation, and allow both individual athlete profiles and squad-wide overviews.
If you're already an Action Apps user, then just start collecting the relevant data (at least, quarterly assessments are recommended) and the maturation reports will populate. If you're not yet a client, but keen to learn more about Action Apps and their Power AMS, take a look at my demo of their AI-powered assistant, AAVA, and visit their website.
Monitoring growth and maturation is not just a data exercise - it’s about making better decisions for athlete welfare and performance. This information can be used to:
Adapt training loads during PHV
Adjust technical/tactical expectations during coordination changes
Inform long-term selection and development strategies
Identify high-risk periods for injury prevention work
Final Thoughts
Growth and maturation are fundamental to understanding youth athletes. Chronological age only tells part of the story: biological age shapes how athletes respond to training, cope with physical load, and manage injury risk.
By monitoring PHV and maturity status, practitioners can can better navigate the challenges of talent identification, physical development, and injury prevention in youth populations.
The Action Apps maturation dashboards offer a practical, visual solution for applying this knowledge in real-world settings.
📄 Explore more:
Learn more about Action Apps
Watch the full video on 'Why Tracking Growth and Maturation is Essential in Youth Sports'
FAQs on Growth and Maturation Monitoring
What is the difference between growth and maturation?
Growth is the physical increase in body size, while maturation is the biological progression toward full development. They do not always occur at the same rate.
What is peak height velocity (PHV)?
PHV is the period of fastest growth during adolescence. It occurs on average at 11–12 years for girls and 13–15 years for boys, but individual timing varies.
How can PHV be measured in practice?
The maturity offset equation (Mirwald et al., 2002) uses standing height, sitting height, body mass, age, and sex to estimate how far an athlete is from PHV. It should be repeated periodically to track trends.
Why is PHV important for training?
Maturation affects how athletes adapt to training. Pre-PHV athletes may benefit most from speed and coordination work, while post-PHV athletes can respond better to strength and hypertrophy programmes.
Does PHV affect injury risk?
Yes. Rapid growth can disrupt coordination and increase vulnerability to overuse injuries, so training loads should be managed carefully during this period.
What is bio-banding?
Bio-banding groups athletes by biological age or maturity status instead of chronological age, helping to create fairer competition and development opportunities.
How often should we monitor growth and maturation?
The necessary somatic measurements should be taken at a minimum on a quarterly basis, although monthly or bi-monthly measurements are common during times of rapid growth, allowing for accurate tracking of growth velocity and timely intervention.
This article is support by Action Apps. For more information about their services, visit their website.
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