Supporters of Nicholas Taylor and David Wagner of the United States present giant faces during the Quad Doubles Wheelchair Tennis Gold Medal match on day 7 of the London 2012 Paralympic Games at Eton Manor on Sept. 5, in London, England.

USA's Nicholas Taylor (R) and David Wagner (L) on their way to winning gold in the Wheelchair Tennis Mens Doubles final on centre Court at Eton Manor in the Olympic Park during the London 2012 Paralympic Games,

Nicholas Taylor of the United States and teammate David Wagner celebrate after the Quad Doubles Wheelchair Tennis Gold Medal match on day 7 of the London 2012 Paralympic Games at Eton Manor on Sept. 5, in London, England.

US Alexandra Raisman competes in the Floor Exercise final at the London 2012 Olympic Games Artistic Gymnastics competition, on London, Aug. 7.

Alexandra Raisman of the United States competes in the Artistic Gymnastics Women's Floor Exercise final on Day 11 of the London 2012 Olympic Games at North Greenwich Arena on Aug. 7, 2012 in London, England.

Alexandra Raisman of the U.S. competes in the women's gymnastics floor exercise final in the North Greenwich Arena during the London 2012 Olympic Games on Aug. 7.

Alexandra Raisman of the United States competes in the Artistic Gymnastics Women's Floor Exercise final on Day 11 of the London 2012 Olympic Games at North Greenwich Arena on Aug. 7, in London, England.

Alexandra Raisman of the United States competes in the Artistic Gymnastics Women's Floor Exercise final on Day 11 of the London 2012 Olympic Games at North Greenwich Arena on Aug. 7.

Alexandra Raisman of the United States hugs coach Mihai Brestyan after winning the gold medal for the Artistic Gymnastics Women's Floor Exercise final on Day 11 of the London 2012 Olympic Games at North Greenwich Arena on Aug. 7, in London, England.

Alexandra Raisman of the US celebrates with her gold medal in the women's floor exercise at the London 2012 Olympic Games Artistic Gymnastics, on Aug. 7.

United States' Conor Dwyer, left, Ryan Lochte, center, and Ricky Berens, right, celebrate as Michael Phelps closes in on their team's gold medal win in the men's 4 x 200-meter freestyle relay at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 31.

United States' Michael Phelps dives in to start the last leg of the men's 4 X 200-meter freestyle relay before their gold medal win at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 31.

United States swim team members, from left, Ryan Lochte, Conor Dwyer, Ricky Berens and Michael Phelps walk with a U.S. flag after being awarded the gold medal for their win in the men's 4 x 200-meter freestyle relay at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 31.

US swimmer Missy Franklin carries a national flag from the podium after receiving her gold medal after winning the women's 100m backstroke final swimming event at the London 2012 Olympic Games on July 30, in London.

Missy Franklin of the U.S., who took first place, starts in the women's 100m backstroke final at the London 2012 Olympic Games at the Aquatics Centre, on July 30.

United States' Missy Franklin competes in the women's 100-meter backstroke swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 30.

United States' Missy Franklin, left, leads in the women's 100-meter backstroke swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 30.

United States' Missy Franklin reacts after winning gold in the women's 100-meter backstroke swimming final at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, on July 30.

Gold medalist Missy Franklin of the US celebrates with her gold medal on the podium after winning the women's 100m backstroke swimming event at the London 2012 Olympic Games on July 30, in London.