How it works
Athletes run once around a 400m track and clear ten evenly-spaced hurdles in the process. They start from blocks placed in staggered positions and run in lanes.
A reaction time – measured by sensors on the blocks – of less than 0.100 is deemed a false start and all the runners are recalled. Any athlete responsible for a false start is disqualified immediately. An athlete can also be disqualified if he or she steps or runs outside their designated lane.
Men clear hurdles that are 36in (91.4cm) high; women negotiate 30in (76.2cm) barriers. The hurdles are knocked down easily if touched, which allows the athlete to continue even if he or she collides with them.
The first 440-yard hurdles race was staged in Oxford, England, circa 1860. Competitors had to tackle 12 huge (100cm) wooden barriers that were sunk into the ground.
The 400m hurdles became a standard discipline for men at the 1900 Olympics. Eighty-four years later, women contested the event at the Games in Los Angeles.
Did you know
When Nawal El Moutawakel of Morocco won the inaugural women’s title in 1984, she became the first African female Olympic champion, as well as the first champion from an Islamic nation.
The USA has racked up 18 Olympic titles in the men’s event. The Caribbean nations also pose a strong threat. Surprisingly USA’s women have never won Olympic gold but they remain one of the stronger nations, along with Russia and Jamaica.
Unbeaten for 122 races between 1977 and 1987, the long-striding US athlete is the greatest 400m hurdler. He landed Olympic gold in 1976 and 1984 and won two world titles (1983 and 1987).
The Brit is the only woman to simultaneously hold Olympic, world, European and Commonwealth titles. She dominated the event between 1992 and 1994.