The men's 50-kilometer, or 31-mile, racewalk is the longest athletic race in the Olympic Games. Although racewalking debuted at the 1908 Olympics, the 50-km race was not introduced until the 1932 Olympic Games. Today, 20-km men's and women's events are also offered.
Unlike running, rules state that the back toe may not leave the ground until the heel of the front foot has touched; it must appear that one foot is in contact with the ground at all times. The athlete's supporting leg must also straighten at the point of ground contact, and the knee must not bend until the body passes directly over it.