INDIANAPOLIS — Aaron Peirsol broke his own world record in the 100-meter backstroke Saturday night, swimming a surprising 53.17 seconds in the U.S. trials for this summer's world championships.
Peirsol, who won three Olympic gold medals last year, had a time of just under 55 seconds in the preliminaries. He said he wasn't thinking of lowering his mark of 53.45 set at the Athens Games.
"I think it's rare you surprise yourself like that," Peirsol said. "It's good that I still can.
"I've done a lot at my level, and to still surprise myself once in a while . . . it was interesting," the 21-year-old said, grinning, as he accepted congratulations from other swimmers at poolside. "I don't know what that was all about."
Peirsol took off about four months after the Olympics.
"Maybe I took it up to the next level and didn't know it," he said. "Maybe taking all that time off last semester really did help me revive my body. I don't know what I did. But cool, man, whatever happened, it's good."
Randall Bal of Stanford was second at 54.01 seconds, and Matt Grevers of Northwestern was third at 54.59.
The winner of each event is guaranteed a spot on the U.S. team that will compete in the world championships July 24-31 in Montreal. Depending on multiple-event winners, second-place finishers could be added to the American squad.
The six-day meet ends on Wednesday.
Michael Phelps, who won eight medals at Athens, and 15-year-old Katie Hoff, who set an American record in the 200 individual medley on Friday, became the meet's first double-winners Saturday night.
Natalie Coughlin, who won five Olympic medals, failed to qualify in the 100-meter butterfly Friday and was scratched from the 200 freestyle before winning the 100 backstroke Saturday night. She set the world record in that event three years ago.
"I really didn't even decide what to swim until about seven days ago," she said. "My main thought was to do the 100 back and the 100 freestyle, and then last week I decided to do the 100 fly."
Coughlin, a gold medalist in the 100 backstroke at Athens, suffered a stress fracture in her left foot while training last September. She finished a disappointing third in the butterfly on Friday but won the backstroke at 1:01.08, well off her record time of 59.58 seconds.
Jeri Moss was second at 1:02.30.
"I was happy with both performances, tonight and yesterday," Coughlin said. "I just started training again in January, and I'm not the most prepared. But I knew I could at least pull it off in the 100 backstroke.
"I'm just looking forward to getting back into real training and getting ready for the summer," Coughlin said.
Phelps, who won the 400 freestyle Friday night, added a win in the 200 free with a time of 1:46.44. He and the next three finishers — Peter Vanderkaay, Klete Keller and Ryan Lochte — automatically qualified for the 800 relay at the world meet. That same quartet surprised the favored Australian team by winning the gold at Athens last year.
"I just wanted to see the best time I could get, and I was pretty pleased with that," said Phelps, whose winning time was more than a second slower than his American record and more than 2 seconds slower than the 1:44.06 world mark held by Australia's Ian Thorpe.
"I would have liked to have been out a little faster, but I can't complain with what's been going on and trying to get back into training," he said.
Phelps was away from swimming for more than a month after the Olympics.
"This is something we're going to build off of, and hopefully when we get to Montreal, that race will be faster," he said.
Phelps did not compete in the 200 butterfly, an event in which he set a world record at 1:53.93 two years ago. Davis Tarwater of Michigan won that event Saturday night at 1:58.71.