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
2007 World Championships in Athletics – Women's 100 metres hurdles 2007 World Championships in Athletics – Women's 100 metres hurdles The 100 metres hurdles at the 2007 World Championships in Athletics was held at the Nagai Stadium in Osaka, Japan from August 27 to August 29. Bursting from the blocks in the final, Susanna Kallur took a narrow lead over the first hurdle slightly ahead of defending champion Michelle Perry. Over the next two hurdles, Kallur established a half metre gap on Perry, with returning silver medalist Delloreen Ennis-London almost matching Perry. After the fifth hurdle, Ennis-London started to spend more time in the air over the hurdles, losing ground.