United States' women's 4 X400-meter relay team from left, Francena McCorory, Allyson Felix, Sanya Richards-Ross and Deedee Trotter celebrate after winning the gold medal during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 11, 2012. (AP Photo/Anja Niedringhaus)

Photo by: Anja Niedringhaus

United States' women's 4 X400-meter relay team from left, Francena McCorory, Allyson Felix, Sanya Richards-Ross and Deedee Trotter celebrate after winning the gold medal during the athletics in the Olympic Stadium at the 2012 Summer Olympics, London, Saturday, Aug. 11, 2012. (AP Photo/Anja Niedringhaus)