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USA's Allyson Felix celebrates their win in the Women's 4x100m Relay final at the World Athletics Championships in Daegu, South Korea, Sunday, Sept. 4, 2011. (AP Photo/Anja Niedringhaus)

U.S. sprinter Allyson Felix

Track and field star Allyson Felix is currently vying for the final U.S. spot on the women's 100-meter Olympic team, after reaching a dead heat with Jeneba Tarmoh.