Sprint Mechanical Adaptations to Small-Sided Games According to Football Players' Biological Age

To analyze the effects of 8-weeks of small-sided games (SSGs) training on the sprint force-velocity profile of youth football players, with special focus on potential baseline differences and training responses according to players' biological maturity status. Male football players (age: 13.9 ± 0.8years) were allocated to an experimental group (n = 49) or a control group (n = 30). The experimental group performed two SSGs sessions per week, integrated into regular team training, with progressive overload (e.g. intensity). Participants completed a maximal effort 30m linear sprint, from which sprint force-velocity variables were assessed, including theoretical maximal force (F₀), maximal velocity (V₀), maximal power (P_max), maximal ratio of force application (RF_max), rate of decrease in force ratio (DRF), and maximal sprint velocity (V_max). Players were stratified according to the predicted years from/to their peak height velocity (PHV): pre-PHV experimental (n=21), pre-PHV control (n = 15), post-PHV experimental (n = 28), and post-PHV control (n=15). A repeated measures ANOVA was performed to show group baseline differences as well as time and interaction effects. Post-PHV players displayed higher baseline values in all anthropometric (body mass, height) and sprint force-velocity variables compared with pre-PHV peers (p < .050). The F₀, V₀, P_max, and V_max improved after intervention compared to controls, independent from players PHV (no time×group interactions). Youth football players with advanced maturity status exhibited higher values in the sprint force-velocity variables compared to their peers with delayed maturity status before the intervention. However, the SSGs training program induced similar force-velocity profile gains for both maturity groups.