Sports Dalilah Muhammad breaks world record in 400 hurdles at US Track and Field Championships July 28, 2019 Cody Goodwin, Des Moines Register Comments Off on Dalilah Muhammad breaks world record in 400 hurdles at US Track and Field Championships Muhammad broke a 16-year-old world record in the 400-meter hurdles, finishing in 52.20 seconds Sunday at the U.S. championships in Des Moines, Iowa.