Michael Phelps swims during a training session of the U.S. swimming team at the main pool of the Aquatics...
Michael Phelps swims during a training session of the U.S. swimming team at the main pool of the Aquatics Centre before the start of the London 2012 Olympic Games in London July 24, 2012. REUTERS/David Gray (BRITAIN - Tags: OLYMPICS SPORT SWIMMING)