Slagle was recognized as an All-American after a sixth-place finish in the outdoor 1,500 meters at the 1982 Association for Intercollegiate Athletics for Women (AIAW) National Championships. Slagle also qualified for the national meet in the 3,000 meters that same year and in the 3,200-meter relay in 1981 and 1982. She was the Virginia AIAW 1,500 meters champion in 1981 and 1982 and also a member of the Dukes' 3,200-meter relay team, which took home top honors in the state in 1982. In 1982, she was the Virginia 1,500-meter run champion after having captured the title in the 800-meter run in 1981.