Beyond chronological age: maturity offset is positively associated with performance in throwing-related tests in...

This study examined the influence of maturity offset, defined as distance from age at peak height velocity, on sport motor test performance in female and male youth track and field throwing athletes aged 13-19 years. The aim was to improve test interpretation and support valid talent identification.

A retrospective data analysis was conducted on 468 observations (female: n = 252; male: n = 216) from 379 junior throwing athletes (female: n = 205, age: 15.5 ± 1.2 y; male: n = 174, age: 15.4 ± 1.1 y). Maturity offset was estimated with the widely used non-invasive Mirwald method. Performance was assessed using a standardized test battery including sprints, jumps, power-oriented throwing tests and a 12-minute run. Associations between maturity offset and test performance were analyzed using linear mixed-effects models.

Higher maturity offset was positively related to performance of throwing-related tests, corresponding to an increase of 12.8% (95% CI: 10.3, 15.3; β = 0.37) in the backward overhead shot throw and 11.9% (95% CI: 9.7, 14.1; β = 0.38) in the forward shot throw for athletes who had a maturity offset that was one year higher than their same-aged peers. Effects on other motor tests were small to trivial (-2.9 to 2.3% performance difference; β = -0.14 to 0.14).

Maturity offset affects physical test outcomes in youth throwers, especially in power-related throwing tasks. These findings highlight the importance of considering maturity offset when interpreting test results to reduce bias in talent identification and better support long-term athlete development.