Bio-banding in youth elite soccer players: a pilot study

Introduction: By the age of 12 to 16 years the biological age (BA) can differ in the same chronological age (CA) group up to five years and affects the athlete’s physical and psychological abilities. Early developed players show superior strength, speed, willingness to take responsibility and leadership, which may play a decisive role in the talent identification and development (1). Bio-banding describes the grouping of young athletes based on their BA rather than the CA in order to reduce the differences in maturity. So far, research investigated the qualitative effects of bio-banding on psycho-social parameters (1). The aim of the underlying pilot study was to quantify the effects of bio-banding on technical, tactical and physical parameters in youth elite soccer games.
Methods: 61 male and two female youth elite soccer players from two Swiss top club’s youth academies U13 and U14 participated in the study. All participant’s peak height velocity was estimated with the Mirwald-Method and the BA calculated. On a single match-day, 4x20 min matches were played. For two matches, the teams were grouped based on the BA. As a control condition, two matches were played with the conventional CA grouping. All matches were monitored ball-oriented with video cameras for the subsequent analysis of technical and tactical parameters. Physical parameters were determined using GPS (ASI, Field Wiz). Data between the bio-banded and control condition were compared using a paired t-test and Wilcoxon signed-rank for non-normally distributed samples. In addition, Cohen’s d effect sizes were calculated.
Results: Within bio-banding, the number of duels increased (p=.02, d=.89) and resulted in a reduced time per action on the ball (p=.01, d=.58). Also, the number of standard situations increased (p=.03, d=1.0) and the percentage of successful passes decreased (p<.01, d=1.23). Medium effect sizes indicated a decreased difference of ball possession [%] (p=.08, d=0.68) within bio-banding. Physical data showed a reduced total running distance (p<.01, d=0.28).
Conclusion: The increased number of duels may indicate a reduced dominance of the early maturing players and consequently may create more opportunities for late maturing players. The reduced time per action on the ball might result from the accelerated match play. Bio-banding created a more balanced and competitive match play and possibly results in a better environment for the development of talented players. From a coach’s perspective, bio-banding could improve the talent identification and selection process and help to detect potential future champions.