THE NEED FOR BRAKES: A FIELD-BASED INSIGHT INTO DECELERATION DEFICIT IN YOUTH FOOTBALL

Purpose: Acceleration and deceleration are key components of football performance. While sprint ability often develops early in youth athletes, braking capacity may not develop in parallel, potentially leading to a neuromuscular imbalance between propulsive and braking abilities. This study investigated the association between sprint and deceleration ability, and biological maturation in U15 football players. Methods: Thirty-two U15 male football players (age: 14.5 ± 0.3 years) were assessed for linear sprint performance over 10 m and 15 m distances and underwent an on-field deceleration test to calculate the deceleration deficit (DD) 1. Maturity offset (MO) and age at peak height velocity (APHV) were estimated using the Mirwald’s equation. Based on 10 m sprint times, athletes were divided into tertiles (faster, moderate, and slower) for group comparisons. Pearson’s correlations and one-way analysis of variance (ANOVA) with Tukey’s post-hoc tests were used to examine relationships between sprint time, DD, and maturation variables. A simple linear regression was also conducted to evaluate whether sprint performance could predict DD. Results: DD showed a significant negative correlation with 10 m sprint time (r = – 0.566, p\0.001), but no with MO and APHV. The one-way ANOVA revealed that slower players had significantly lower DD than both moderate (p = 0.012) and faster (p = 0.006) groups. No difference was found between faster and moderate athletes (p = 0.978). Linear regression confirmed that sprint time significantly predicted DD (b = – 0.566, p\0.001), explaining 32% of its variance (R2 = 0.321). Conclusions: Faster young players tend to exhibit higher deceleration ability, independently of biological maturation. These findings highlight a neuromuscular mismatch between propulsive and braking abilities, underscoring the need for brakes in U15 youth football players through targeted deceleration-focused training. References: Clarke R, Read PJ, De Ste Croix MBA, Hughes JD. The Deceleration deficit: a novel field-based method to quantify deceleration during change of direction performance. J Strength Cond Res. 2022;36(9):2434–2439.