MICHAEL PHELPS

THINGS HAVE CHANGED for Michael Phelps, who returned to competition in April after 20 months of retirement. At the U.S. Swimming National Championships in Irvine, Calif., last week, the 18-time Olympic champion qualified for the team that will compete at the Pan-Pacific Championships in Australia later this month. But for the first time since 2000, Phelps left nationals without winning a race. "The biggest difference I notice is the time it takes him to recover," says his coach, Bob Bowman. "He can be good on a Tuesday or Thursday, but he can't be good on every day of the week." Now 29, Phelps has made numerous adjustments since he won his first Olympic medal in 2004.

, but he's doing this because he wants to and he's smiling when he comes to practice. At this point in his life he wouldn't be doing this otherwise."

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Phelps's time in a 100-meter butterfly prelim at the U.S. championships, best in the world this year.

51.21

Phelps's time in his gold-winning 100 butterfly swim at the 2012 Olympics.

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SIMON BRUTY/SPORTS ILLUSTRATED (PHELPS)

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PATRICK SEMANSKY/AP (PHELPS'S BACK)

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GETTY IMAGES (BARBELL)

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MARK WEISS/GETTY IMAGES (STEAK)

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PETER READ MILLER/SPORTS ILLUSTRATED (PHELPS IN WATER)

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MANNY FLORES/CSM (PHELPS'S SHOULDER)

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FLOREA MARIUS CATALIN/VETTA/GETTY IMAGES (GREENS)