FILE - United States' Allyson Felix crosses the line to win gold in the women's 4x400-meter final during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Saturday, Aug. 20, 2016. On Friday, July 15, 2022, in a 4x400 mixed relay, Felix will bid adieu once and for all to the track scene. (AP Photo/Matt Slocum, File)