Michael Phelps smiles on the podium before being presented with the gold medal in the men's 100-meter butterfly swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, August 3, 2012. Phelps picked up his 17th Olympic gold medal. (AP Photo/Michael Sohn).
United States' gold medallist Michael Phelps, front, walks with South Africa's silver medallist Chad le Clos behind him after the medal ceremony for the men's 100-meter butterfly swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, August 3, 2012. (AP Photo/Matt Slocum).
South Africa's Chad le Clos, left, congratulates Michael Phelps for winning the gold in the men's 100-meter butterfly swimming final (AP Photo/Matt Slocum).
Michael Phelps is seen on a large display as he stands for the U.S. national anthem after he was presented with a gold medal in the men's 100-meter butterfly swimming final (AP Photo/Lee Jin-man).
Michael Phelps reacts after receiving the gold for the men's 100-meter butterfly swimming final (AP Photo/Matt Slocum).
Michael Phelps spits water out of his mouth after winning the men's 100-meter butterfly swimming final (AP Photo/Lee Jin-man).
Michael Phelps puts on his gold medal in the men's 100-meter butterfly swimming final (AP Photo/Lee Jin-man).
Michael Phelps, center, South Africa's silver medallist Chad le Clos, left, and Russia's bronze medallist Evegnu Korotyshkin display their medals for the men's 100-meter butterfly swimming final in the Olympic Park during the 2012 Summer Olympics (AP Photo/Matt Slocum).
