This study aims to investigate the effects of an 8-week high-intensity interval training (HIIT) program on aerobic capacity, anaerobic power, blood lactate levels, and sprint performance in young male soccer players. Twenty-four volunteer U19-category soccer players from Sivasspor A.Ş. were randomly allocated into an experimental group (n=12), which performed HIIT three days per week for 8 weeks in addition to their regular training, and a control group (n=12), which continued only their routine training program. Anthropometric measurements, resting heart rate, aerobic performance (Yo-Yo IRT1), anaerobic performance (RAST), and blood lactate levels were assessed before and after the intervention period.