Understanding the Impact of Biological Maturation on Agility in Youth Soccer Players

Biological maturation drives the largest agility gains between Pre‑ and Circa‑peak height velocity (PHV) in youth soccer players, a primary analysis of determinants of agility shows.

PHV marks the period of fastest adolescent growth and is commonly used to stage maturation in youth sport research; framing results by PHV enhances practical translation for coaches and clinicians. This pattern is immediately relevant for how training and assessment priorities are sequenced across development.

The observational cross‑sectional study included 63 youth soccer players split into Pre (n = 14), Circa (n = 15) and Post (n = 34) PHV groups and assessed reactive and linear performance endpoints. The testing battery—reactive shuttle test, pro‑agility test, short linear sprints, and vertical jumps—was standardized across participants to support comparability and stage‑specific interpretation. Reactive shuttle time decreased substantially from Pre‑ to Circa‑PHV, with large effect sizes that indicate both statistical and practical significance and suggest a concentrated maturational window for targeted training emphasis.

Reaction time and lower‑limb power emerged as the dominant predictors of agility, with stage‑specific weighting: reaction time explained the most variance in Pre‑PHV, while squat‑jump power dominated in Circa‑PHV. Reported regression models had high explanatory power (Pre R² = 0.79; Circa R² = 0.85), with reaction time β ≈ 0.69 in Pre and squat‑jump β ≈ −0.26 in Circa. Inter‑individual variation in early reaction time narrowed by Circa‑PHV as power measures improved—supporting a focus on perceptual reaction work in Pre‑PHV and explosive power development in Circa‑PHV to align training with the dominant determinants.

Change‑of‑direction (COD) deficit — the time lost switching directions relative to linear sprint speed — increased with maturation even as jump and sprint metrics improved, and was longest in Post‑PHV. The pattern likely reflects greater momentum and deceleration demand with advancing size and speed, underscoring that COD capacity must be trained and monitored as a distinct quality. Limitations include the cross‑sectional design, which prevents causal inference, and modest subgroup sizes; longitudinal and intervention studies are needed to confirm causality and refine stage‑specific prescriptions.

Maturity‑specific emphasis is warranted: reaction‑time and perceptual drills for Pre‑PHV, and controlled force‑application plus power drills for Circa‑PHV, with careful load management to limit injury risk. Monitoring should include periodic reassessment across the season and after PHV transitions, since maturation can shift performance priorities. Documenting individual responses to stage‑specific drills will help balance progression and injury prevention. Importantly, maturity‑adjusted benchmarks reduce the risk of premature deselection when larger, faster adolescents are compared on raw scores—so COD deficit should be tracked alongside sprint and jump outputs and included in routine assessments.