title: Men are more likely than women to slow in the marathon.
abstract: Studies on nonelite distance runners suggest that men are more likely than women to slow their pace in a marathon.
  
  
  OBJECTIVE
  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 were acquired from 14 US marathons in 2011 and encompassed 91,929 performances. For 2929 runners, we obtained experience data from a race-aggregating Web site. We operationalized pace maintenance as the 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, as follows: "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% confidence interval, 1.41-1.50; P < 0.0001) times higher than men to maintain the pace and 0.36 (95% confidence interval, 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 < 0.0001). 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 less 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.
authors.affiliation: 1Department of Psychology, Grand Valley State University, Allendale, MI; 2Department of Health Sciences Research, Mayo Clinic, Rochester, MN; 3Department of Anesthesiology, Mayo Clinic, Rochester, MN; and 4Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Deaner
authors.forename: Rickey E
authors.initials: RE
authors.lastname: Carter
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Joyner
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Hunter
mesh_terms: D000367:Age Factors; D003163:Competitive Behavior / Q000502:physiology*; D003657:Decision Making; D005260:Female; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology* / Q000523:psychology; D012737:Sex Factors; D013997:Time Factors