Who says girls can't compete athletically with boys?

Joel Stager, professor in the School of Health, Physical Education and Recreation at IU Bloomington, said he is not suggesting that boys and girls compete against each other, but he said his findings indicate they could.

"It's the whole perception that girls can't compete fairly with boys," he said. "Well, at certain ages, they can."

The study analyzed data provided by USA Swimming that consisted of the best 50-yard freestyle performances for all USA Swimming-registered male and female swimmers ages 6 to 19 who competed from 2005 to 2010. This included 1.9 million swims.

The study found no difference in swim performance in children younger than 8. It also found little difference in 11- and 12-year-olds. The effects of puberty began showing in the older swimmers, as the boys began experiencing accelerated growth in height, weight and strength typical of age 13 and older.

Researchers chose to analyze children's performance in the 50-yard freestyle because the swimmers' performances were less influenced by training per se and more likely to be influenced by muscle function. A second study further characterizes the "distribution of performance" within the entire U.S. Swimming database, something that has never been done before for a competitive event.

"Sex Differences in Childhood Athletic Performance" was discussed May 31 at the annual meeting of the American College of Sports Medicine in San Francisco May 29 to June 2. Co-authors are lead author Andrew Cornett and Karen Kafadar, Eastern Michigan University.