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
2005 World Championships in Athletics – Women's 100 metres hurdles the lead while Hayes again was matching Perry stride for stride until Hayes hooked the ninth hurdle. She lost her balance between hurdles so much she never jumped the tenth hurdle, instead carrying it some seven metres down the track before pushing it away and striding over the finish line in last. With her last challenger suddenly out of the race, Perry ran in to the finish with a 1-metre lead over Ennis-London, who was less than a half metre ahead of her teammate Foster-Hylton across the line for silver. All times shown are in seconds.<br> Q denotes qualification by