FILE - In this July 28, 2012, file photo, Michael Phelps competes in a heat of the men's 400-meter individual medley at the 2012 Summer Olympics in London. After retiring and then un-retiring, Phelps will be in Rio as the first U.S. male swimmer to compete in five Olympics. (AP Photo/Michael Sohn, File)
•August 4, 2012
Olympic champion Michael Phelps has announced his intention to retire after the London Olympics.