Pacing Strategy During 24-hour Ultramarathon-Distance Running

Purpose: This study aimed to describe pacing strategy in a 24-h ultramarathon-distance running race held on a flat course and its interaction with sex, age group and athletes’ performance group. Methods: Data from 398 male and 103 female participants in 5 consecutive editions were obtained based on a minimum 19.2-h (80% duration) active-running cut-off. Mean running speeds from each hour were percentage normalized to the total 24-h mean speed in order to eliminate the effect of between-runner differences in absolute speed. Results: Mean performance of all editions was 135.5 ± 33 km with a mean active-running time of 22.4 ± 1.3 h. Overall data showed a reverse J-shaped pacing strategy with the exception of a significant reduction in speed during the last hour. Two-way mixed ANOVA showed no significant interactions between racing time and sex (F = 1.57; P = 0.058) and racing time and age group (F = 1.25; P = 0.053), but significant interactions were found between racing time and performance group (F = 7.01; P < 0.001). Person’s product-moment correlations showed a moderate association between total running distance and normalized mean running speed in the first two hours (r = -0.58; P < 0.001) but not in the last two (r = 0.03; P = 0.480). Conclusions: In 24-h ultramarathons, while the general behaviour represents a reverse J-shaped pattern, the fastest

runners started at lower normalized mean running speed, displaying a more even pacing strategy compared to the slower counterparts, regardless of sex and age group.