Background/objectives. This study aims to analyse the speed differences between men and women in the 400 meters during the Paris 2024 Olympic Games. Average speeds in each segment of the race were evaluated, highlighting gender variations and performance across the different rounds of the competition. Methods. A descriptive observational study was conducted using data from 208 athletes (50% women). Average speeds per 50-meter segments were analysed across all rounds (heats, semifinals, and final), applying Student's t-tests to compare results between genders. The significance level was set at p < .05. Results. The average speeds showed significant differences between sexes in all segments of the race (p < .05). The largest difference was observed in the first 150 meters, where men outpaced women by a margin of 0.97 km/h. By 250 meters, the difference decreased to 0.43 km/h. In the final rounds, the winners reached maximum speeds of 36.87 km/h (men) and 32.48 km/h (women). Conclusion. Men exhibit a biomechanical advantage in the race's early stages, while both sexes strategically adjust their pacing in the final rounds. These findings suggest that gender differences in performance are linked to both physiological and biomechanical factors.