Biological maturity influences running performance in junior Australian football

Abstract

Objectives

The purpose of this study was to investigate the influence of biological maturity on measures of running fitness and running performance in both training and competition in junior Australian football.

Design

Cross sectional observational.

Methods

Fifty-two male junior players from five age groups (U11–U19) participated. Biological maturity was self-assessed based on Tanner's description of five pubertal stages (P1–P5) as well as objectively estimated from anthropometric measures and expressed as years to and from peak height velocity (Y-PHV). Running speed and aerobic fitness were measured using a 20 m sprint and 20 m multi-stage shuttle run respectively. Running movements during training and competition were analysed (n = 197) using global positioning system technology, including total distance, peak speed, high-intensity running (HIR > 14.4 km/h) distance and number of sprints (>23 km/h).

Results

Age groups included participants from a range of pubertal stages (U11: P1–2; U13: P2–4; U15: P2–5; U17: P4–5; U19: P5). Y-PHV was significantly correlated with 20 m shuttle run (r = 0.647), 20 m sprint time (r = −0.773) and all distance and high intensity running variables (r = 0.417–0.831). Incremental improvements across pubertal stages for speed, aerobic fitness and most GPS derived running variables were observed. Within age group comparisons between less and more mature players found significant differences for standing and sitting height, peak speed in training, and total distance, HIR and peak speed in matches.

Conclusions

Functional running fitness and running performance in both training and competition environments improved with increasing biological maturity. More mature players in an age group, either chronologically, biologically or a combination of both, are at a performance advantage to those less mature.

Introduction

Sports governing bodies generally apply age groupings for youth athletes in an attempt to provide equitable competition and development for athletes of similar chronological age.1, 2, 3 Children and adolescents, however, do not mature at the same rate⁴ while sporting age groups typically span one or two years resulting in athletes in a single competition with up to two years difference in chronological age.³ It is also known that biological age can vary as much as three years in individuals of the same chronological age.⁵ As children mature, increased height and weight have an impact on aerobic and anaerobic capacities, muscular strength, power and running speed, leading to an improved sporting performance throughout pubertal growth.⁵ This gives a distinct advantage in sporting performance to older individuals or those more biologically mature within an age group.⁶

The relative age effect (RAE) refers to the predominance of selected players born in the first quarter or half of the year in annual age-grouped cohorts that have been shown to result in short-term and long-term differences in sport outcomes as a result of birth date.1, 2 Explanations for the RAE typically include a combination of chronological age and physical characteristic differences due to greater maturity. Older individuals in the same age group have a physical and performance advantage, with this advantage being greater for early maturing compared to late maturing players.2, 7

Outcomes linked to the RAE usually focus on selection into elite training programmes and representation in teams and squads at both junior and senior levels,2, 3 however some researchers have also assessed comparative differences in measures of physical fitness⁸ and skill.⁹ Malina¹⁰ further considered the association between relative skeletal age and injury risk in elite schoolboy soccer players concluding that maturity status and time spent in match play and training were significant predictors of injuries.

The RAE is well documented in the football codes² although the phenomenon is not always associated with significant advantages in physical components.¹¹ Furthermore, little is known about the influence of age and maturation on match running performance in football, although Buchheit et al., have explored this issue in soccer.¹² Time-motion analysis data are not available in the literature across the development pathway for junior Australian football (AF), a sport characterised by similar running demands to soccer at the elite level13, 14 along with the addition of considerable physical contact.¹⁵ More specifically the influence of age and biological maturation on running performance has not been described in this cohort. The purpose of this study therefore was to investigate the influence of biological maturity on measures of running fitness and running performance in both training and competition in junior AF.