Full coverage: 2016 Rio Olympics

The spectacle's most decorated athlete Michael Phelps is seeking more medals. The American turned 31 on Thursday, and celebrated by becoming the first swimmer to qualify for five Olympiads.

The 22-time medalist, 18 of those gold, was competing at the U-S trials in the 200-metre butterfly. He would come first touch the wall in a time of one minute, 54.84 seconds, three second off his world record time.

With the victory, Phelps will have a shot at reclaiming the Olympic title he won in 2004 and 2008 but surrendered that crown to South African Chad le Clos at the 2012 London Olympics.

The American has trimmed back his programme for Rio, and will only try to qualify in two other events, the 100 butterfly and 200 individual medley.