Researchers who studied data from 10 of the nation's largest 10-km races between 2002 and 2011 found that women today make up the majority of runners in these races, although men run faster.
The top runners are finishing in shorter time, and the faster men are also increasingly younger, the study of 400,000 participants also showed.
However, "it's not just elite runners or former high school athletes running today's 10-km races; there are more everyday people running this distance," study author Dr. Dan Cushman, a clinical instructor in physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine in Chicago, said in a university news release.
"One of the best things we can do to improve our health is exercise and taking on a 10-km race is a great goal," he added.
More competitors are completing these 6.2-mile races in under an hour, with increasingly more women accomplishing this feat than men, according to the study, published online in the Journal of Strength and Conditioning Research.
Referring to the growing participation of women in these races, Cushman said, "Coaches and trainers can use this information to develop more women-specific 10-km training programs to accommodate this surge of female middle-distance runners."
In 2010, 1.3 million people participated in 10-km races in the United States, according to the news release.
The American Academy of Orthopaedic Surgeons offers tips for a safe running program.