Michael Johnson

Shattered world record in 200m (19.32) and set Olympic record in 400m (43.49) to become first man to win the gold in both races in the same Olympic Games at Atlanta in 1996; two-time world champion in 200 (1991,95) and four-time world champ in 400 (1993,95,97,99); set world record in 400m (43.18) at '99 world championships in Seville; won the 400 in Sydney in 2000 to become the only man to win the event in two consecutive Olympics; retired in 2001.