This scientific article examines the methodology for developing endurance in middle-distance runners in athletics. The study analyzes the theoretical foundations of endurance, the ratio of aerobic and anaerobic loads, and the specifics of planning the training process. The effectiveness of the proposed training methodology was evaluated through a pedagogical experiment involving control and experimental groups. The results demonstrate a significant improvement in general and special endurance indicators among athletes in the experimental group. The findings of the study can be applied in the training practice of middle-distance runners to enhance athletic performance.