(Reuters) - American teenager Katie Ledecky set a world record in the 400 meters freestyle at the U.S. National Championships in Irvine, California on Saturday, while Michael Phelps struggled home in sixth in the 100m backstroke.
The 17-year-old Ledecky clocked 3 minutes, 58.86 seconds to better the previous record of 3:59.15 held by Italy’s Federica Pellegrini. The Italian’s mark was set in 2009 before high-tech polyurethane swimsuits were banned.
Ledecky, who became the first American to hold the 400, 800 and 1,500m freestyle world records at the same time since Janet Evans, took her latest record-breaking performance in stride.
“Honestly, I didn’t think about it too much,” the 2012 Olympic 800m freestyle champion told NBC sports. “I just wanted to put together a good swim and go a best time. I did, so I‘m happy.”
Ledecky, the reigning 400m world champion, came close to the world record with a time of 3:59.89 in the morning heats.
She went out hard in the final and was under record pace at halfway by more than a second when she turned at 1:57.72.
When Ledecky touched at 300m more than 1.5 seconds ahead of Pellegrini’s mark, a world record seemed almost a formality.
She slowed over the next lap to hit 350m in 3:29.41, just .38 seconds ahead of world record pace, but it was enough of a cushion and she held on to touch the wall .29 faster than Pellegrini’s mark.
Phelps, meanwhile, made a slow start and was never in contention in the 100m backstroke as Olympic and world champion Matt Grevers won in 52.75, the third fastest time in the world this year.
On the comeback trail after coming out of retirement, Phelps was more than a second behind in 53.95 though given the event has never been one of his strongest, and he has never contested it at the Olympics, his performance was not a huge surprise.
The U.S. team are a powerhouse in the event and Americans have won the past five Olympic titles.
“Whatever I really put my mind to, I know I can accomplish,” said Phelps. “I’m not going to use the excuse of taking off (nearly two years).”
In the most significant meet since Phelps launched his comeback in May, the 18-times Olympic champion finished seventh in the 100m freestyle on Wednesday and second in the 100m butterfly on Friday.
He is also scheduled to swim the 200m individual medley on Sunday.
In the women’s 100m backstroke, Missy Franklin clinched her fifth straight national title in 59.38, which ranks her third in the world this year. Her time was significantly slower than the 58.33 she recorded to win the event at the 2012 Olympics.
In other events, Michael McBroom edged Matt McLean to win the men’s 400m freestyle in 3:47.19.
Jessica Hardy and Micah Lawrence tied in the women’s 100m breaststroke in 1:06.51, while Cody Miller won the men’s race in 59.91.
Reporting By Andrew Both in Cary, North Carolina; Editing by Peter Rutherford