United States' LaShawn Merritt places ice onto his injured hamstring following his heat of the men's 400 meters during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Martin Meissner)

Photo by: Martin Meissner

United States' LaShawn Merritt places ice onto his injured hamstring following his heat of the men's 400 meters during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 4, 2012. (AP Photo/Martin Meissner)