Effects of high-intensity interval training sprint interval running with changes of direction on aerobic and anaerobic capacity of youth soccer players

Abstract

Background: High-intensity interval training (HIIT) and sprint interval training (SIT) have proven efficacy in improving aerobic and anaerobic capacities in athletes. However, there are still gaps in soccer-specific protocols that incorporate change-of-direction (COD) maneuvers for youth players. Traditional soccer training often results modest performance improvements, particularly during competitive seasons. This highlights the need for time-efficient, ecologically valid interventions that enhanced performance while reducing injury risk. Purpose: This study investigated the effects of an 8-week SIT protocol involving 20s maximal-effort runs with COD on aerobic and anaerobic performance in male U17 soccer players during the 2024-2025 competitive season. Methods: Thirty male U17 academy soccer players (age: 16.2 ± 0.4 years) were randomized into an experimental group (EG, n=17) and control group (CG, n=27). The EG performed 3 weekly sessions of SIT: 120-m sprints with zigzag COD (two 45° turns, one 90° turn) at supramaximal intensity (~20 s per rep), followed by 100 s passive recovery (7 reps per 1 sets, ~15–20 min total). The CG continued standard technical-tactical training. Pre- and post-intervention assessments included VO₂max (graded treadmill test), Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1), and Running-based Anaerobic Sprint Test (RAST) for anaerobic power/fatigue. Results: The EG exhibited significant aerobic gains: VO₂max increased by 6.21% (from 44.83 ± 3.12 to 47.61 ± 2.89 ml·kg⁻¹·min⁻¹; t = –11.38, p < 4.42×10⁻⁹, r = 0.943), and Yo-Yo IR1 distance by 34.96% (1004.7 ± 152.3 to 1336.47 ± 178.4 m; t = –11.26, p < .001, r = 0.939). The CG showed smaller improvements: VO₂max +1.52% (50.57 ± 2.45 to 51.32 ± 2.31 ml·kg⁻¹·min⁻¹; t = –7.01, p < 1.90×10⁻⁷, r = 0.809) and Yo-Yo IR1 +6.15% (1685.92 ± 210.5 to 1776.29 ± 198.7 m). Anaerobically, EG RAST total peak power output rose 13.80% (2802.92 ± 245.6 to 3189.59 ± 267.4 W; t = –10.92, p < .001, r = 0.939), versus CG +4.37% (t = –7.75, p < .001, r = 0.835). Effect sizes were large to very large, with EG outperforming CG across metrics. Conclusions: The 20s SIT with COD elicited profound physiological adaptations, substantially enhancing aerobic (VO₂ max, intermittent endurance) and anaerobic (power, fatigue resistance) capacities beyond standard training. These findings demonstrate that short-burst SIT with COD elicits superior dual-system adaptations in youth soccer players, enhancing match-relevant performance with minimal time commitment. Practical implications include integrating such protocols in-season to optimize physiological development without overtraining risk. Future research should explore long-term effects and female cohorts.