United States' Allyson Felix competes in the women's 400-meter final during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Monday, Aug. 15, 2016.
United States' Allyson Felix competes in the women's 400-meter final during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Monday, Aug. 15, 2016. Lee Jin-man AP
United States' Allyson Felix competes in the women's 400-meter final during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Monday, Aug. 15, 2016. Lee Jin-man AP