An analysis of the nation's largest 10-kilometer road running races show that women are in the majority. Researchers analyzed data from more than 400,000 runners who participated in 10 of the largest 10K (6.2 mile) races in the U.S. from as early as 2002 through 2011.  

10K races have become increasingly popular in the U.S. over the past decade, with 1.3 million people participating in such races in 2010. Women began outnumbering men in the 2006 and 2007 time-frame and today make up the majority of runners who participate in these 10 large 10K races in the U.S., according to Dan Cushman, M.D., lead author of the study and  clinical instructor in physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine and chief resident at the Rehabilitation Institute of Chicago. 

Other findings from the Northwestern Medicine analysis include:

• The top groups of men and women appear to be getting faster
• The fastest men are also increasingly younger
• There are more sub-hour finishers, with increasingly more women accomplishing this feat compared to men
• An increasing percentage of finishers, however, are completing races in more than one hour

"It seems that as these large races have more people participating, we have slower runners, but I see that as a positive thing," said Cushman. "It's not just elite runners or former high school athletes running today's 10km races, there are more everyday people running this distance. One of the best things we can do to improve our health is exercise and taking on a 10km race is a great goal.

"Coaches and trainers can use this information to develop more women-specific 10km training programs to accommodate this surge of female middle-distance runners."

Published in the Journal of Strength and Conditioning Research. Source: Northwestern University