Jamaica's Usain Bolt reacts after a men's 100m semifinal heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Sunday, Aug. 5, 2012. (AP Photo/Matt Slocum)

Photo by: Matt Slocum

Jamaica's Usain Bolt reacts after a men's 100m semifinal heat during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Sunday, Aug. 5, 2012. (AP Photo/Matt Slocum)