United States' Aries Merritt celebrates winning gold in the men's 110-meter hurdles final during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London (AP photo)

Aries Merritt celebrates winning gold in the men's 110-meter hurdles final during the athletics in the Olympic Stadium. (AP photo)

Aries Merritt celebrates winning gold in the men's 110-meter hurdles final during the athletics. (AP photo)

Aries Merritt, left, crosses the finish line in the men's 110-meter hurdles final to win gold ahead of Jamaica's Hansle Parchment during the athletics . (AP photo)

Aries Merritt, left, crosses the finish line in the men's 110-meter hurdles final to win gold ahead of Hansle Parchment during the athletics. (AP photo)

Aries Merritt, left, crosses the finish line ahead of United States' Jason Richardson, right, and Jamaica's Hansle Parchment, center, to win gold in the men's 110-meter hurdles final. (AP photo)

Aries Merritt, right, beats teammate Jason Richardson, top and Jamaica's Hansle Parchment to win the men's 110-meter hurdles. (AP photo)

Aries Merritt clears a hurdle in a men's 110-meter hurdles heat during the athletics in the Olympic Stadium. (AP photo)

Aries Merritt, center, wins the men's 100-meters hurdles final as Cuba's Dayron Robles is left behind during the athletics. (AP photo)

Aries Merritt crosses the finish line ahead of Jamaica's Hansle Parchment to win the men's 110-meter hurdles final during the athletics. (AP photo)

Aries Merritt leads his heat in the men's 110-meter hurdles during the athletics. (AP photo)

Aries Merrit clears a hurdle in a men's 110-meter hurdles heat during the athletics. (AP photo)