United States' Michael Phelps displays his gold medal for the men's 100-meter butterfly swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Friday, Aug. 3, 2012. (AP Photo/Matt Slocum)
Gabrielle Douglas of the U.S. competes on the balance beam during the women's individual all-around gymnastics final in the North Greenwich Arena during the London 2012 Olympic Games August 2, 2012.
Tyler Clary of the U.S. sings his national anthem with his gold medal on the podium after winning the men's 200m backstroke final during the London 2012 Olympic Games at the Aquatics Centre August 2, 2012.
United States' Rebecca Soni celebrates winning gold and setting a new world record in the women's 200-meter breaststroke swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Aug. 2, 2012.