I recently attended a student Sport Science workshop hosted by AFC Bournemouth. The event was curated by lead academy Sport Scientist Ben Bradley. Other speakers included James Bunce (Head of Sport Science at the Premier League) and Dan Hodges (AFC Bournemouth 1st Team Head of Sport Science). Although all presentations were extremely interesting, a topic that I found particularly interesting and was covered in both Ben, and James’ presentation was that of Bio-Banding. Bio-Banding aims to group young players together according to their physical maturity rather than their age. AFC Bournemouth along with a hand full of other clubs have been innovative in implementing this technique within their academies, in the attempt to allow an even playing field throughout the development of a young player. This blog will explore the maturation process, what bio-banding is and why it is being used in football academies.
Peak Height Velocity (PHV)
PHV is a period a maturation in which an adolescent experiences their most rapid growth spurt (Lloyd, Oliver, 2012). The PHV coincides with the onset of puberty, and occurs on average at age of 14 for boys (Balyi, Hamilton, 2004) and last for approximately 2 years. However, although this is the average age, the actual age at which a boy will experience this phase of maturation is highly variable. This is demonstrated in the study by Chuman, Hoshikawa, Iida & Nishijima (2014) where PHV was shown to vary from as young as 11 years, up to the age of 15 years.
PHV is a period a maturation in which an adolescent experiences their most rapid growth spurt (Lloyd, Oliver, 2012). The PHV coincides with the onset of puberty, and occurs on average at age of 14 for boys (Balyi, Hamilton, 2004) and last for approximately 2 years. However, although this is the average age, the actual age at which a boy will experience this phase of maturation is highly variable. This is demonstrated in the study by Chuman, Hoshikawa, Iida & Nishijima (2014) where PHV was shown to vary from as young as 11 years, up to the age of 15 years.
Why is PHV Important?
Before during and after PHV appear to periods in which the athlete may be more sensitive to certain types of training (i.e., hypertrophy, strength, power). These periods have been identified as periods of accelerated adaptation (Lloyd, Oliver, 2012) and may influence conditioning design. Therefore, identifying an athletes PHV can assist in developing a training programme that is relevant to the athletes’ level of maturation. For example, Rump, Cronin, Oliver & Hughes (2012) showed that preadolescents benefit from training that involves high levels of neural activation (sprint and plyometrics) whereas adolescents respond better to training that targets neural and muscular development. Below is the Youth Physical Development Model from Lloyd and Oliver (2012).
(Lloyd & Oliver 2012)
Measuring PHV
The PHV may be estimated using a simple equation. The variables requires are standing height (cm), sitting height (cm), date of birth and weight (kg). It must be appreciated that this is only an estimation, and there can be an error of 6 month variance on each side. The full equation is below:
Maturity Offset = -9.236 + (0.0002708 x leg length and sitting height interaction) + (-0.001663 x age and leg lenth interaction) + (0.007216 x age and sitting height interaction) + (0.02292 x weight by height ratio)
(Sherar et al., 2005)
The equation results in the number of years the athlete is from experiencing PHV. A reference table can then be used to infer their predicted adult height. It is recommended that these measurements are taken 2-3 times throughout the year as a childs growth rate has a tendency to fluctuate. This may also improve accuracy of the estimation.
Bio-Banding
Too often players are rejected from academies on the premise of their physicality. This is evident in players such as Harry Kane who was released from Arsenal at age 11 due to size, Jamie Vardy at Sheffield Wednesday and even Roy Keane at Bright and Hove Albion.
There is a proven bias towards clubs selecting players based on whether they were born in the first quarter of the UK academic year (September-November) as they are generally bigger, therefore early developers.
A handful of academies are now introducing the concept of bio-banding, which groups players together in relation to their biological age rather than their chronological age in attempt to provide an even playing field for player development. This attempts to identify early and late developers with a view to eliminating the problem of the early maturer relying on their physicality to get them through games, while helping the later maturers who may be at a risk of being overlooked. It creates a platform for everyone to compete and a fresh opportunity to maximise the players technical development.
Using the equation above, players are grouped together into three bands, 80-85%, 86-91% and 91-97% of predicted adult height (PAD). At AFC Bournemeouth the players still play normal league matches within their own age group, but certain training sessions and in house tournaments are used to bio-band the players and offer a different perspective.
With the variation in age seen in the bio-banded groups, interesting outcomes have been noticed. For example the players that were not so dominant, or natural leaders in their own age group, were seen to show more confidence and improved leadership skills. Older players in the group were also able to pass on their wisdom, teach younger players and take more of leadership role.
This concept can be taken even further with physiological testing carried out within bio-bands. This could potentially give a more accurate representation of where the player actually is terms of physicality.
Biological age is an area that still requires further research to investigate the possible effects it may have on young developing footballers. Nevertheless, it provides a high level of idividualisation within training programes which can only be a good thing as a one size fits all approach is not acceptable. This is a really interesting area of study and essential for any practioner entering the academy system.
References
- Lloyd, R.S., and Oliver, J.L. (2012). The Youth Physical Development Model: A New Approach to Long-Term Athletic Development. Strength and Conditioning Journal, 34(3), pp.61-72
- Balyi, I., and Hamilton, A. (2004). Long term athlete development: Trainability in children and adolescents; windows of opportunity. National Coaching Institute: Canada
- Chuman, K., Hoshikawa, Y., Iida, T., and Nishijima, T. (2014). Maturity and intermittent endurance in male soccer layers during the adolescent growth spurt: A longitudinal study. Football Science, Vol.11, 39-47
- Rumpf., MC, Cronin, JB., and Hughes, MG. (2012). Effect of different training methods on running sprint times in male youth. Paediatric Exercise Science.
- Sherar, L.B., Mirwald, R.L., Baxter-Jones, A.D.G. and Thomis, M. (2005) ‘Prediction of adult height using maturity-based cumulative height velocity curves’, The Journal of Pediatrics, 147(4), pp. 508–514.
