Abstract
Background
The timing and magnitude of sex differences in athletic performance during early human development, prior to adulthood, is unknown.
Objective
To compare swimming velocity of boys and girls for all Olympic-length freestyle swimming events to determine the age of divergence in swimming performance.
Methods
We collected the all-time top 100 U.S. freestyle swimming performance times of boys and girls age 5 to 18 years for the 50m to 1500m events.
Results
Swimming performance improved with increasing age for boys and girls (p