Studies of non-elite distance runners suggest that men are more likely than women to slow their pace in the marathon.
Purpose: This study determined the reliability of the sex difference in pacing across many marathons, and after adjusting women's performances by 12% to address men's greater maximal oxygen uptake and also incorporating information on racing experience.
Methods: Data was acquired from 14 U.S. marathons in 2011, and encompassed 91,929 performances. For 2,929 runners, we obtained experience data from a race-aggregating website. We operationalized pace maintenance as percentage change in pace observed in the second half of the marathon relative to the first half. Pace maintenance was analyzed as a continuous variable and as two categorical variables: "maintain the pace," defined as slowing < 10%; and "marked slowing," defined as slowing >=30%.
Results: The mean change in pace was 15.6% and 11.7% for men and women, respectively (P<0.0001). This sex difference was significant for all 14 marathons. The odds for women were 1.46 (95% CI: 1.41 to 1.50, P<0.0001) times higher than men to maintain the pace and 0.36 (95% CI: 0.34-0.38; P<0.0001) times that of men to exhibit marked slowing. Slower finishing times were associated with greater slowing, especially in men (interaction, P<.0001). However, the sex difference in pacing occurred across age and finishing-time groups. Making the 12% adjustment to women's performances lessened the magnitude of the sex difference in pacing but not its occurrence. Although greater experience was associated with lesser slowing, controlling for the experience variables did not eliminate the sex difference in pacing.
Conclusions: The sex difference in pacing is robust. It may reflect sex differences in physiology, decision making, or both.
(C) 2014 American College of Sports Medicine