Pacing and Body Weight Changes During a Mountain Ultramarathon: Sex Differences and Performance

Area of Science:

• Exercise Physiology
• Sports Science
• Endurance Sports

Background:

• Pacing strategies significantly influence performance in endurance events.
• Understanding sex-based differences in ultramarathon pacing is crucial for optimizing training and race execution.
• Intracompetition body weight changes and sedentary time are potential indicators of physiological stress and pacing adherence.

Purpose of the Study:

• To compare pacing strategies between male and female athletes in a 107-km mountain ultramarathon.
• To investigate the association between pacing variables, intracompetition body weight changes, and overall performance.
• To identify sex-specific differences in sedentary time and body weight fluctuations during the ultramarathon.

Main Methods:

• Forty-seven athletes (29 males, 18 females) underwent pre-race cardiopulmonary exercise testing.
• Athletes were weighed at multiple points: pre-race, mid-race (33km, 66km, 84km), and post-race.
• Pacing was analyzed using speed variations and accelerometry-derived sedentary time.

Main Results:

• Females exhibited significantly less sedentary time (2.62 ± 2.14%) compared to males (4.72 ± 2.91%).
• Females experienced smaller body weight loss (3.01 ± 1.96%) than males (4.37 ± 1.77%).
• Even pacing (lower speed variability, higher pacing index) and reduced sedentary time correlated with better finishing times.

Conclusions:

• Female ultramarathon runners may benefit from shorter aid station breaks, contributing to less body weight loss.
• A more consistent pacing strategy is positively associated with enhanced performance in mountain ultramarathons.
• Intracompetition body weight changes should be analyzed alongside running speed dynamics to fully understand race performance.