INDIANAPOLIS, United States (AFP) - Six-time Athens Olympic swim champion Michael Phelps withdrew from the 400-meter individual medley here Friday at the World Short Course Championships due to a back injury.
Phelps, who won the 200 freestyle title Thursday, came into the meet with a sore back and took an unplanned rest day on the advice of doctor Jim Johnson. His status for the remaining three days of competition was uncertain.
"Michael is going to sit out the 400 IM because of tightness in his back," Johnson said. "He has had a long month on the road. We decided it's better for him to rest today so he can finish the rest of his events strong."
Phelps was not included in the United States lineup in Friday's 4x200 freestyle relay final. Phelps is scheduled to swim the 200 IM Saturday, two 100 IM races Sunday and the 100 IM and 200 butterfly finals on Monday.
Phelps won Olympic gold in the 200 and 400 IMs, 100 and 200 butterfly, the 4x200 free relay and 4x100 medley relay but missed Mark Spitz's record of seven golds, settling for 200 freestyle and 4x100 free relay bronzes.
After his eight-medal effort in Greece, Phelps went on a month-long US tour that concluded Tuesday with an appearance at Disneyland in California. He has made television appearances and attended the Ryder Cup golf matches.
Phelps won the 200 freestyle for his first world short course crown in 1 min, 43.59 secs with top qualifier Rick Say of Canada second in 1:44.39.
"I was feeling pretty bad the last 75m," Phelps said after the race. "I was definitely in pain but I was satisfied with the time."
With top rivals such as Australians Ian Thorpe and Grant Hackett and Dutchman Pieter van den Hoogenband absent, Phelps has emphasized having fun at this meet, largely swimming here to boost swimming's US profile.
More than 550 swimmers from 97 nations are competing at the seventh world short course event in a temporary 25m pool at a basketball arena.
The smaller pool forces Phelps to make more turns than in the long-course 50m pool and each turn puts greater stress upon his back.
Phelps admitted he still feels tired after his Olympic effort and said after his victory that nothing would come easy at the meet.
"There's probably going to be a lot of tough races," he said. "I'm glad I have one under the belt."