The 110-meter race has ten high hurdles (1.067 meters [42 inches] high) placed 9.14 meters (10 yards) apart. The 400-meter race takes place over ten intermediate hurdles (91.4 cm [36 inches] high) positioned 35 metres (38.3 yards) apart. A hurdle is a vertical post with a horizontal crosspiece on which a footbridge is hung. Hurdlers are used in races where the distance is not enough for full runners. At the beginning of the 20th century, they were added to standard race distances to provide an easier challenge for those who could not handle the pain of regular running. Today, only the 110-hurdle race remains part of any major championship schedule. There are also several smaller hurdling events that may be run as qualifiers for larger competitions or as stand-alone events. During a 110-hurdle race, each athlete runs between one and nine times across the course. If an athlete crosses the finish line before all ten hurdles have been jumped, then he or she completes the race. To calculate how many hurdles an athlete must jump to win, divide the length of the course by the time it took to cross all ten hurdles. For example, if an athlete crossed the finish line in 50 seconds, then he or she had jumped five times. This means that the winner ran two miles (3.2 kilometers) while trying to beat his or her personal best time of 50 seconds.