 Complete the following phrase:  Delisa Walton-Floyd born Delisa Walton, 28 July 1961 is a former World-Class middle distance runner who specialized in the 800 metres; she was a two-time National Collegiate champion, and two-time U.S. Open champion in her event. Delisa Walton-Floyd represented the United States at the 1987 Pan American Games; winning a silver medal at 800 meters. Walton-Floyd also competed at the World Championships in 