United States' women's 4 x100-meter relay team members, from left, Tianna Madison, Carmelita Jeter, Bianca Knight, and Allyson Felix, pose with the timing board displaying their world record time of 40.82 seconds during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Friday, Aug. 10, 2012. (AP Photo/Matt Dunham)