Katie Ledecky, making her debut as a professional swimmer, set a world record in the 1,500-meter freestyle on Wednesday, swimming a time of 15 minutes, 20.48 seconds to lower her own world record by five seconds.
Ledecky, who holds freestyle world records in the 400 and 800, as well, broke the 1500-meter record of 15:25.48 she had set at the 2015 World Championships in Kazan, Russia.
The 21-year-old was competing in a USA Swimming Pro Series meet at the Natatorium at IUPUI in Indianapolis, and she finished more than 49 seconds ahead of second-place finisher Erica Sullivan.
Ledecky, who won four gold medals at the 2016 Olympics, is entered in six more events at this week's meet: the 100-, 200-, 400- and 800-meter freestyles, as well as the 200- and 400-meter individual medleys. The competition continues through Saturday
A five-time Olympic gold medalist, Ledecky swam for Stanford in college, but she announced following the 2017-18 season that she would go pro and skip her final two years of collegiate swimming.