Pacing and performance during the World 24-Hour Mountain Bike Championships.

INTRODUCTION: Pacing is crucial for optimal performance in ultra-endurance events (1). This study investigated the impact of sex, category and athletes’ performance capacity on pacing and performance during the World 24-hour Mountain Bike Championships. METHODS: Data from 837 men and 157 women in 8 editions of the race (2012-2019) were analysed. Athletes who covered more than two times the standard-deviation of the mean distance from each edition and completed more than 19.2 h (80% of total time), were included in the analysis. They were categorised based on age (e.g. under-23, 23-29, 30-34, 35-39, etc) or as elite and single-speed bike, and ranked into 5 performance-groups based on distance covered (i.e. groups 1 and 5 were the fastest and slowest clusters of athletes, respectively). Differences in performance between sexes were analysed using independent-samples t-test. Pacing was assessed by normalising the speed during the first, middle and last laps to the mean race speed and analysed with one-way repeated-measures ANOVAs. Differences in pacing between sexes, categories and performance-groups were analysed with two-way repeated-measures ANOVAs (P < 0.05). Pearson correlations were used to calculate associations between normalised speed during the first-lap and total distance covered. RESULTS: Mean distance covered and final time were 275.9 ± 67.2 km and 23.7 ± 1.1 h, respectively. Men covered 278.5 ± 69.3 km and women 262.0 ± 57.6 km (5.9% difference; P = .005). Elite athletes covered longer distances than all other categories (P < .001), except for under-23 (P = .128). Decreases in normalised speed from the first lap were found throughout all races (P < .001). Significant interactions were found between pacing and categories, and performance-groups (both P < .002, Effect size [ES] > .022), but not sex (P = .550, ES < .01). Performance-group 1 adopted a slower normalised speed in the first lap in relation to groups 3-5 (P < .001), and a higher speed in the last lap in relation to groups 4-5 (P = .010). Correlations indicated an inverse moderate association between speed during the first lap and total distance covered (r = -.358, P < .001). CONCLUSION: Our results indicate that on average, athletes adopt a positive pacing strategy (i.e. decreasing speed from the first lap) during 24-hour mountain bike races. Men and women display similar pacing strategies, while performance was similar for elite and under-23 categories. However, faster athletes adopt a lower initial normalised speed, and a less pronounced decrease in the last lap, than slower athletes. This suggests that cyclists should adopt conservative initial speeds during the early stages of 24-hour mountain bike races to improve overall performance, although this may be dependent on experience, self-confidence and accurate knowledge of their performance capacity. REFERENCES: 1. Abbiss & Laursen. Sports Med,2008; 38: 239-252.