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Hurdling is a track-and-field event in which runners race over a series of obstacles along a course. The obstacles, called hurdles, are set a fixed distance apart. During a race, runners must remain in their assigned running lanes. Although they may knock hurdles down while running over them, they may do so only with a leg or foot, not a hand. The first hurdler to complete the course is the winner.

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Modern hurdlers use a sprinting style between hurdles. While clearing a hurdle, they lean the upper body forward as the lead leg is extended straight ahead to skim the obstacle. They then bring the trailing leg through at nearly a right angle to the body. This enables them to continue forward without breaking stride after clearing the hurdle. The object is to make the hurdling action smooth and rhythmic so as not to disrupt forward progress.

In the Olympic Games and other major outdoor competitions, the hurdling distances for men are 110 meters (120 yards) and 400 meters (440 yards). The 110-meter race includes 10 high hurdles, 1.07 meters (42 inches) high. They are spaced 9.14 meters (10 yards) apart. The 400-meter race is over 10 intermediate hurdles, 91.4 centimeters (36 inches) high, that are spaced 35 meters (38.3 yards) apart.

For women, the standard hurdling distances are 100 meters (110 yards) and 400 meters. In the 100-meter event, women clear 10 hurdles that are 84 centimeters (33 inches) high and spaced 8.5 meters (27.9 yards) apart. The women’s 400-meter race includes 10 low hurdles, 76.2 centimeters (30 inches) high. For both men and women, distances and specifications vary for indoor and scholastic events.

Hurdling probably originated in England in the early 19th century. Such races were held at Eton College about 1837. In those days, competitors ran from one hurdle to the next, slowed down, and jumped over the obstacles with both feet together. Alvin Kraenzlein, who won four gold medals at the 1900 Olympic Games in Paris, France, was a pioneer of the modern technique of leading with a straight leg over the hurdles. Later innovators in the sport included Edwin Moses, who went unbeaten in the 400-meter hurdles from 1977 to 1987. He virtually revolutionized the event by taking only 13 strides between each hurdle. At the time, his competitors typically took one or two additional steps.

Women’s hurdling—in the form of an 80-meter race—was first included in the Olympics at the 1932 Games in Los Angeles, California. Babe Didrikson Zaharias won that inaugural Olympic race. The women’s 100-meter hurdles replaced the 80-meter event at the 1972 Olympics in Munich, West Germany (now in Germany). The women’s 400-meter hurdles debuted as an Olympic event at the 1984 Games in Los Angeles.