Bio-Banding in Youth Basketball
The relative age effect (RAE) has been studied throughout a number of sports over a period of years. RAE has been shown in a number of studies in the selection of youth basketball players.1-5 RAE is the idea that older players within a year are disproportionately represented in team selections, especially on youth teams.3 Players born in Quarter 1 (January through March) are overrepresented, whereas those born in Quarter 4 (October to December), and often Quarters 2 and 3, are underrepresented.
These results should not surprise, as coaches choose players who can help the team win, which often leads to choosing maturity or age over potential or skill. I spoke to my athletic director during tryouts this year and said if the goal was to win as many games as possible, only 6-7 players looked like actual varsity players.
I suggested keeping more players, and attempting to schedule some junior-varsity games, as I felt the younger players were better at basketball; they were just small and less mature. Two of our four most skilled players were 8th graders, but they struggled with the size and athleticism against some teams. The multi-sport juniors and seniors who were not really basketball players fared better in some games just because they could match the size, strength, and athleticism, at least on defense, even if they lacked the same shooting, passing, and dribbling skills of the younger players.
This example is more extreme, as we had one team for four grades and pulled up two middle-school players — we had 13-18 year-olds on one team — but the idea holds within narrower age ranges: Coaches often identify maturity, size, and strength, not skills, talent, and potential.
Chronological age and biological age are not the same, but young athletes with a six to ninth-month age advantage often are further along in their maturation when trying out at U14, U16, and U18. Late maturers often struggle to be selected to national teams, participate in talent identification programs, and train with more experienced coaches.6 The effects tend to dissipate at the professional levels, and some have found an underdog effect: The late birthdates or late maturers have an advantage later in their careers when they catch up in size and strength, provided they remain in the competitive stream long enough for the maturational differences to even out.7-8 However, the perceived lack of opportunity may cause frustration, lack of interest, and early dropouts.6 Players must overcome these negative effects and persist to benefit from the underdog effect.
Competitive levels are based entirely on chronological age or grade levels.6 Grade-based leagues, such as school sports, often change the effects. I have a September birthdate; I was always one of the oldest in my class, and consequently on school teams in middle school, but one of the youngest on my age-based recreation teams like soccer and baseball. Naturally, I was better at basketball (point guard) than baseball (2nd base) or soccer (right midfield). My small advantage in maturity created more opportunities, as I played more, handled the ball more, etc., whereas I had fewer opportunities, fewer at-bats, less influence on the game, and more in baseball and soccer. Small skill differences between my peers and I at the outset widened through greater and lesser opportunities, based largely on initial maturational differences, but we identify these discrepancies as talent.
Few leagues consider maturation when selecting teams or designing leagues despite these well-researched effects, but some countries and federations have experimented with biological-age competitions, referred to as bio-banding.6 Bio-banding attempts to create more equitable competition at younger ages, separating early maturers and average to late maturers by the percentage of their predicted adult height.6 These competitions allow for a balanced physical game encouraging a greater variability in actions for the late maturers and a greater challenge for the early maturers.6
A modified game (lower basket heights, shorter three-point line) in U13 games did not affect the early maturers, but enhanced the participation and performance of late maturers. The type of opposition influenced the physical performance and spatial exploration behaviors, particularly of the late maturers.9 The increased efficiency in shooting and passing in the modified game tends to generate greater perceived efficiency, self-efficacy, enjoyment, and satisfaction, which enhances motivation and learning.6
One criticism of developmental basketball is the inequitable competition. Every weekend, teams play games decided by 20-30 points, often resulting in running clocks (less game time), arguments about pressing or playing to win, and more. Typically, the better teams are not necessarily better coached, but due to bigger, stronger, more mature players. The bigger, better players gain little by winning easily against lesser competition, and the smaller players likely gain little by playing against competition too far beyond their current level.
Bio-banding is one idea to combat these lop-sided games, although organizing such leagues would take more work and run counter to the recruiting to win, stacking talent team development that currently permeates through youth basketball. Rather than acquiring the most mature players, coaches, clubs, and teams would have to develop better players within a narrower (biological) age range to be competitive.
Again, this takes work. However, every week, another well-paid consultant, expert, or executive bemoans the current state of play in youth sports. Youth sport is a billion-dollar industry. Why not use these resources, financially and the man-power of the consultants and experts displeased with the current game, to experiment with potential improvements such as bio-banding? If the goal is to create better experiences for children, why not adjust competitions for more equitable competition to provide for better development for all involved? Why invest all the resources into the early maturers just because they can help a team or coach win immediately? Bio-banding is not the cure for all problems in youth basketball, but it has the potential to solve many issues.
Short of incorporating bio-banding league-wide, coaches should be aware of maturational differences between players. Burying a player just because he was born in December, not January, may cause a potentially good player for the club or school to quit, whereas involving the player and giving him minutes may lead to the underdog effect in the future. Most of all, acknowledging maturational differences will cause coaches to reflect more deeply when selecting teams, rather than immediately gravitating to the big, more mature players. This reflection also will force coaches to articulate their goals: Are they trying to win as many games as possible this season or to develop a long-term program? More questioning and more reflection almost always leads to better outcomes, whether or not bio-banding is incorporating officially.
References
Chittle, L., Horton, S., & Dixon, J. C. (2016). Time out or fast break? The relative age effect in NCAA Division I basketball. Journal of Sport Behavior, 39(2), 107-25.
Delorme, N., & Raspaud, M. (2009). The relative age effect in young French basketball players: a study on the whole population. Scandinavian Journal of Medicine & Science in Sports, 19(2), 235-42.
Kelly, A.L., Jiménez Sáiz, S.L., Lorenzo Calvo, A., de la Rubia, A., Jackson, D.T., Jeffreys, M.A., ... & Santos, S.D.L.D. (2021). Relative age effects in basketball: exploring the selection into and successful transition out of a national talent pathway. Sports, 9(7), 101.
Leite, N., Borges, J., Santos, S., & Sampaio, J. (2013). The relative age effect in school and federative sport in basketball. Revista de Psicología del Deporte, 22(1), 219-22.
Torres-Unda, J., Zarrazquin, I., Gravina, L., Zubero, J., Seco, J., Gil, S. M., ... & Irazusta, J. (2016). Basketball performance is related to maturity and relative age in elite adolescent players. The Journal of Strength & Conditioning Research, 30(5), 1325-32.
Birrento-Aguiar, R.A., Arede, J., Leite, N., García-Angulo, F.J., Pino-Ortega, J., & Ortega-Toro, E. (2023). Influence of two different competition models on physical performance in under-13 basketball players: Analysis considering maturity timing. Applied Sciences, 13(22), 12125.
Kelly, A.L., Wilson, M.R., Gough, L.A., Knapman, H., Morgan, P., Cole, M., ... & Williams, C.A. (2020). A longitudinal investigation into the relative age effect in an English professional football club: Exploring the ‘underdog hypothesis’. Science and Medicine in Football, 4(2), 111-18.
McCarthy, N., Collins, D., & Court, D. (2016). Start hard, finish better: further evidence for the reversal of the RAE advantage. Journal of Sports Sciences, 34(15), 1461-65.
Arede, J., Cumming, S., Johnson, D., & Leite, N. (2021). The effects of maturity matched and un-matched opposition on physical performance and spatial exploration behavior during youth basketball matches. Plos One, 16(4), e0249739.