Can Maturation Level Influence Long-Term Physiological and Physical Adaptations in Youth Female Soccer Players Exposed to Combined Sided Games and HIIT? A Comparison Across Maturation Statuses.

The aim of this study was to assess the effects of a 6-week high-intensity interval training combined with small-sided games (HIIT&SSG) program on maximal strength, sprint performance, and aerobic capacity in female athletes and to examine how these effects vary across different stages of maturity (pre-, mid-, and post-peak height velocity [PHV]). Specifically, we sought to determine whether the improvements in performance outcomes were consistent across maturity groups or if the training effects differed based on the athletes' maturity status. Fifty-four female soccer players (aged 9-16 years) were categorized into pre-PHV, mid-PHV, and post-PHV maturity groups. Participants were randomly assigned to either an HIIT&SSG group (n = 27) or a control group (n = 27). The HIIT&SSG group performed two additional training sessions per week, focusing on 2v2 small-sided games and individualized high-intensity runs at 85% of their final velocity during the 30-15 Intermittent Fitness Test (VIFT). Control continued their regular training routines. Pre- and post-intervention assessments included isometric mid-thigh pull (IMTP) for maximal strength, 30-meter sprint time, and VIFT for aerobic capacity. Pre- and post-intervention assessments included isometric mid-thigh pull (IMTP) for maximal strength, 30-meter sprint time, and VIFT for aerobic capacity. The HIIT&SSG group demonstrated large effect sizes for IMTP (ηp