400 metres hurdles to 400 metres, or one lap of the stadium, and the number of hurdles was reduced to ten. The official height of the hurdles was set to 91.4 cm (3 feet) for men and 76.20 cm (2 ft, 6 inches) for women. The hurdles were now placed on the course with a run-up to the first hurdle of 45 metres, a distance between the hurdles of 35 metres each, and a home stretch from the last hurdle to the finish line of 40 metres. The first documented 400 m hurdles race for women took place in 1971. The International Association
100 metres hurdles fall over if bumped into by the runner, but weighted so this is disadvantageous. Fallen hurdles do not count against runners provided that they do not run into them on purpose. Like the 100 metres sprint, the 100 m hurdles begins with athletes in starting blocks. The fastest 100 m hurdlers run the distance in a time of around 12.5 seconds. The world record set by Kendra Harrison stands at 12.20 seconds. The Olympic Games had included the 80 m hurdles in the program from 1932 to 1968. Starting with the 1972 Summer Olympics the women's race was lengthened to