compete in Rio U.S. Olympic swimmer Phelps IOC News (Olympics) マイケル・フェルプス RIO 2016: MICHAEL PHELPS' LAST CHALLENGE retiring Coming out of retirement Phelps was quoted according to the games' governing body Michael Phelps coming out of retirement at 31 increased Phelps told IOC News the Olympic hero. the Olympic hero. Phelps has improved with age Phelps told IOC News whatever it takes Article