Variation Associated to Chronological Age and Bio-Banded Competitive Groups in Youth Soccer
(Jan M. Konarski, Mateusz Skrzypczak, Tomas Oliveira, André Seabra, Manuel J. Coelho-e-Silva, Robert M. Malina)

The aim of the study was to compare the body size, skeletal maturity status and functional characteristics of soccer players aged 9–16 years in competitive chronological age (CA) and bio-banded (BB) groups; the latter were defined by the percentage of predicted adult height (%PAH). Body height, mass and functional capacities (sprints, jumping, agility, strength) were measured for 110 players in four competitive CA groups (U10, U12, U14, U16). Assessments of skeletal age (SA) and predicted adult height (PAH) were based on methods developed in the Fels longitudinal study. Current body height was expressed as %PAH which was used to classify players into BB groups approximating take-off (TO) of the adolescent spurt [BB1, %PAH <85%], the interval between TO and peak height velocity (PHV) [BB2, ≥85<90%], PHV [BB3, ≥90<95%] and post-PHV [BB4, ≥95%]. Characteristics of players in adjacent CA and BB groups were compared. Differences in body size, SA and functional capacities between adjacent CA and BB groups were variable but were most marked between U12 and BB2 players. The latter were older in CA, advanced in SA, taller, heavier and stronger than U12 players, but other functional test results did not differ significantly. Though not as marked, a similar trend was apparent between U10 and BB1, as well as U14 and BB3 players, while differences between U16 and BB4 players were negligible. Allowing for variation within CA and BB groups, the results highlight the potential utility of bio-banding especially among early adolescent and adolescent players (U10, U12, U14). Considering that BB groups are not fixed, they can be modified as needed.