A horse race is a sport in which horses compete over short distances. The sport requires fast acceleration and a strong turn of foot to win. Individual flat races can range in length from 440 yards (400 m) to more than four miles (6 km). Longer races are known as routes or staying races and are seen as a test of stamina. The sport has a number of traditions and is one of the oldest sports in the world. It has benefited from technological advances, such as thermal imaging cameras that detect when a horse is overheating post-race and MRI scanners that can pinpoint injuries or illnesses in a racehorse.
The earliest races would seem familiar to modern fans: winners carried more weight than non-winners, fillies got allowances and there was even an early version of the futurity concept. But it was the arrival of faster Middle Eastern sires that prompted breeding programs to produce leaner, more compact animals capable of putting their speed to good use. These new breeds were called Thoroughbreds and their success increased interest in the sport.
When the first permanent oval tracks appeared in the United States, the sport was revolutionized. The improved viewing angles allowed spectators to watch from a more comfortable position and betting was made easier. It was in this era that horse racing began to take on the characteristics we associate with it today, including a heightened emphasis on health and safety for the animals.
A major factor in the popularity of horse races is the size of the purse. When a race offers a large sum of money to the winner it attracts more entrants, which in turn leads to higher quality runners and more excitement. Purses have become much larger in recent years as the industry has expanded and diversified, but they still represent only about a quarter of the total industry revenue.
Another key factor is the ability of a horse to compete in various conditions. It is important for a trainer to be able to train a horse to run well on dirt, turf and on the synthetic surfaces that are used at many racetracks. A trainer who is not able to do this will have difficulty securing consistent wins for his or her clients.
The most common way to classify a horse is by its race level or grade. A horse that has won a claiming race is moved into the conditioned claiming ranks where it can be matched against horses of similar abilities. If a horse is successful in this group it may eventually be moved into open claiming races where there are no performance limits on the horses entered. A horse with a “good trip” means that it did not encounter any unusual trouble during the race, while a horse with a bad trip may have had to cover ground or was boxed in by other runners. The latter type of horse is often referred to as having a “bad runner.”