Michael Johnson is a retired American sprinter
Johnson have won four Olympic gold medals and eight World Championship gold medals
He is considered one of the most consistent sprinters in the history of track and field
In 1996 Summer Olympics, Atlanta, he became the only male athlete in history to win both 200 and 400 metres events
Johnson is the only man to defend his Olympic title in the 400 metres at 2000 Summer Olympics in Sydney
Johnson has also earned eight gold medals at World Championships