Tracking growth and calculating maturity has multiple benefits for athletes, trainers, and clubs. We briefly summarize the three main benefits below.
Reduce injury burden
Why is the growth spurt a risk factor for injuries?
At the start, during, and immediately after the growth spurt, youth athletes are more prone for injuries. Two factors contribute to this effect:
On the one hand, during the growth spurt, bones grow earlier than the muscles, tendons, and ligaments, which leads to higher stress on the musculoskeletal system. This results in a reduction of the load capacity of the musculoskeletal system, and increases the chance of experiencing both acute and overuse injuries.
A second factor that contributes to the higher injury rate, is that the rapid increase in height and weight can reduce neuromuscular control and stability. This results in a temporary decrease of coordination and technique, and is often referred to as "adolescent awkwardness".
Unfortunately, this period of increased injury risk often coincides with an increase in intensity of sport-specific training and competition. To make matters worse, early maturing athletes are often labelled as "talented" because they are taller, faster, and stronger than their peers. In the period in which they are most prone for overuse injuries, these athletes are then offered extra training sessions, for example by joining a training session of an older youth team once a week. It is therefore no surprise that multiple studies have reported increased prevalence of in injuries during the period of PHV.
Figure 1: The relation between growth speed and injury likelihood. Red indicates higher likelihood for injury.
Tracking growth gives insight into when a player enters the stages of increased risk, and when growth velocity reaches its peak.
Athletes with increased risk for injuries should be provided with developmentally appropriate training programmes. Exact training content is dependent on sport-specific characteristics, but the general goal is the same for each sport: reduce the training load and modify the training content.
Practical suggestions to reduce injury prevalence in this high-risk group:
Reduce repetitive intensive activities such as sprinting and jumping
More attention to technical and tactical aspects
Focus on balance, mobility, coordination, and core stability
Reduce load by training on cushioned surfaces
Case study of successful implementation: AFC Bournemouth (Soccer)
By monitoring growth and adjusting training load and content, AFC Bournemouth reported a 86% reduction in injury incidence among players within their growth spurt.
Figure 2: A heat map showing the combined effects of Growth Rate and Percentage of Predicted Adult Stature on estimated injury likelihood in A) 2018–19 season (pre-intervention) and B) 2019–20 season (intervention).
Reference: Johnson et al., (2023) Can we reduce injury risk during the adolescent growth spurt? An iterative sequence of prevention in male academy footballers
Improve development of early and late maturers
Why do athletes need a maturation specific training environment?
To ensure optimal development of youth athletes, they could be grouped on the basis of biological rather than chronological age. This practice is called bio-banding, and has multiple benefits.
The considerable differences in size and weight between early and late mature athletes can have safety implications, especially in contact sports such as judo or rugby. Matching youth athletes with opponents of similar size and/or maturity will therefore reduce the risk of some athletes being dangerously overpowered by their peers.
Differences in maturity leads to early maturing athletes to rely too much on their physical strength while disregarding technical and tactical skills Late maturing athletes on the other hand experience less success and might even drop out because of this. Bio-banding has shown to restore the competitive equity. In a bio-banded environment, early maturing athletes need to emphasize technique, teamwork, and tactics over physical power, while late maturing players have the opportunity to demonstrate their skills and take a more active part in the game. Both during practice and competition bio-banding can have a positive effect on the motor development and learning experiences of athletes.
Tracking growth could also be of benefit for the physical development of youth athletes. Athlete development models such as the Long Term Athlete Development Model and the Youth Physical Development model suggest that during certain phases of development, a youth athlete is more responsive to certain training. For example, more intensive strength training in function of hypertrophy is suggested to best take place only after PHV, after 95% of PAH.
Practical suggestion and considerations when implementing bio-banding:
Bio-banding should not replace traditional age categories, but should be used in a complementary way.
When creating bio-banded groups, trainers should also take into account injury history, technical proficiency, and psychological development.
Figure 3: example of a bio-banded team
adapted from YouTube: Bio-Banding Opens More Avenues in Player Development. Link in Youtube
Case study** of successful implementation: Premier League academy (Soccer)
The English Premier League organised a tournament for its academy players who were between 85 and 90% PAH. Interviews with the players revealed that both early and late maturing players described the bio-banded games as a positive and welcome addition to their games program, claimed it was beneficial for their development, and recommended to continue with the initiative.
Reference: Cumming et al., (2018) Premier League academy soccer players’ experiences of competing in a tournament bio-banded for biological maturation
Better talent detection
Why is maturity important for talent detection and development?
As early maturing athletes are taller, stronger, and faster than their peers, they perform better in competitions, and are over-represented in talent selections. Due to this selection bias, late maturing athletes are often overlooked and receive less opportunities to further develop their talents. In other words, youth academies run the risk of investing in averagely talented early maturing athletes at the cost of more talented late maturing athletes.
Especially when comparing test results of youth athletes, adjusting for maturity might give a completely different image of the athletic profile of the athletes. For example, results in figure 10 shows that this early maturing athlete is outperforming other athletes in his age category, but when compared to athletes of similar maturity status, he is actually underperforming.
Figure 4: Fitness scores for an under 12 athlete, represented as Z-scores relative to players of the same age (left) and relative to players to the same maturity (right; adapted from Cumming et al. 2017)
In many sports, adult height is an important factor to reach the highest level of competition. However, being early or late mature does not correlate with being taller or shorter as an adult. It is therefore important that youth academies take into account predicted adult height when (de)selecting youth athletes and when assigning talented athletes to a certain positions in the team. For example, a talented youth volleyball player with a predicted adult height of 192cm will have better chances to become a professional athlete as a setter than as a middle blocker.
