Kilit, B, Chmura, P, Arslan, E, Soylu, Y, and Radziminski, Ł. Effects of 2 combined training protocols on the aerobic and anaerobic fitness, technical skills, and psychophysiological responses in young soccer players. J Strength Cond Res XX(X): 000-000, 2024-The study compared the effects of combining small-sided soccer games (SSGs) with high-intensity interval training (HIIT) and repeated sprint training (RST) on aerobic and anaerobic fitness, technical skills, and psychophysiological responses in young soccer players. Thirty-two male, adolescent, soccer players (aged 13.5 ± 0.3 years) were randomly divided into either the SSGs + HIIT group ( n = 16) or the SSGs + RST group ( n = 16) for combined training 3 times per week for 6 weeks. The players in the SSGs + HIIT group performed 12-18 minutes of runs at intensities (90-95%), whereas the players in the SSGs + RST group consisted of 3-4 sets of 5-7 times 15-m shuttle sprints (all-out efforts). Both training groups played 4 bouts of 2-a-side or 4-a-side SSGs with various game formats at 2-day intervals. Psychophysiological responses were determined during and after all training sessions. Before and after training interventions, the following physical performance tests were used: 5- to 30-m sprint time, countermovement jump, triple-hop distance, zigzag agility with the ball and without the ball, repeated sprint ability (RSA), 30-15 Intermittent Fitness Test, 3 corner run test, speed dribbling ability (SDA), Yo-Yo Intermittent Recovery Test Level 1, and Y-balance test. Our main findings were that the SSGs + RST group demonstrated greater improvement in 5-m sprint time, SDA time, and RSA in the meantime compared with the SSGs + HIIT ( p ≤ 0.05, d values ranging from 1.50 to 2.25). Moreover, the SSGs + RST group showed greater improvement in agility test responses ( p ≤ 0.05, d values ranging from 2.13 to 2.34) than the SSGs + HIIT group. However, the SSGs + HIIT induced higher perceived exertion, mental effort, and lower greater physical enjoyment meaningfully compared with the SSGs + RST ( p ≤ 0.05, d values ranging from 6.04 to 6.67). In conclusion, these results demonstrate that the SSGs + RST is an effective training program to improve young soccer players' speed and agility-based performance responses.