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
110 metres hurdles early days were first replaced in 1895 with somewhat lighter T-shaped hurdles that runners were able to knock over. However, until 1935 runners were disqualified if they knocked down more than three hurdles, and records were only recognized if the runner had left all hurdles standing. In 1935 the T-shaped hurdles were replaced by L-shaped ones that easily fall forward if bumped into and therefore reduce the risk of injury. However those hurdles are weighted so it is disadvantageous to hit them. The current running style where the first hurdle is taken on the run with the upper body lowered