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
300 metres hurdles hurdle marks in the same place as the last seven hurdles of the standard 400-metre version, thus Masters only go over seven hurdles. While men of all ages have run over 300 hurdles, the youngest official division to use the distance is M60. M60 and M65 run over 30-inch (76.2 cm) barriers, M70 and M75 run over 27-inch barriers. Prior to 2010, older age divisions also did 300 hurdles, though the number of competitors was small. In 2010, M80+ and women's W70+ moved to doing a 200-metre race over the last five barriers of either race, thus retiring the 300