Chronological, biological, and relative age as determinants of performance in track and field athletes aged 5-17...

This study aims to investigate how chronological, biological, and relative age affect anthropometric measurements and physical fitness in young track and field athletes.

In this cross-sectional study, 460 athletes (292 girls and 168 boys, ages 5-17) from Greek track and field academies were assessed. Each athlete completed standardized anthropometric evaluations that included height, sitting height, leg length, arm span, body mass, and BMI. They also participated in a performance assessment battery, which consisted of 20-meter sprint, Star Agility test, side-to-side jumps, single-leg triple hop, jump-and-reach, handgrip strength (HGS), overhead medicine ball throw (1 kg for athletes aged 5-12.9 years; 2 kg for athletes aged 13-17 years), 20-meter shuttle run (speed, estimated VO2max), stand-and-reach, and Stork balance test. Biological age was estimated using Mirwald equations.

Most anthropometric and performance measures increased across chronological and biological age groups, with higher strength and power values observed in boys closer to peak height velocity (PHV). Chronological age, sex, and anthropometric characteristics accounted for approximately 21-81% of the variance in performance outcomes. Strength- and power-related tests were explained largely by multiple regression models (handgrip adj.R²=0.81; triple jump adj.R²=0.69; medicine ball throw adj.R²=0.674. Flexibility was largely independent of the remaining fitness parameters (ρ=-0.016 to 0.105), whereas balance showed weak-to-moderate associations with performance outcomes (ρ=-0.433 to 0.463). Relative age effect (RAE) was minimal, with only a few inconsistent differences observed among the first and fourth quarters of births.

Growth and biological maturation are key determinants of strength and power performance in youth track and field athletes, while the impact of relative age is limited in this context. These findings support the idea of training and talent identification strategies that are informed by maturity rather than solely by chronological age.