A horse race is a contest of speed or stamina between two or more horses. Horse races have lasted for centuries and they have evolved from primitive competitions to a spectacle involving large fields of runners, sophisticated electronic monitoring equipment, and huge sums of money. The basic concept, however, has remained unchanged: the horse that finishes first is declared the winner.

The earliest known races were held in Ancient Greece and Rome, and the sport grew rapidly during the Renaissance in Europe. By the 17th century, the sport was widely played in Britain and France, where it became a major form of entertainment. The development of breeding programs and stables contributed to the growth of the racing industry, and the sport grew even more popular with the invention of betting.

Horse races are usually run on a flat track with one or more turns. A race may be a handicap race or a stakes race in which the horses carry a fixed amount of weight to ensure a fair match between competitors. The weights are usually determined by the governing body of the race, or by the bookmakers or trainers for a specific race. In the case of a stakes race, the weights may be based on past performance or the horse’s pedigree and current physical condition.

In addition to the horses, races are contested by jockeys and trainers. While modern racing has seen a number of female jockeys, the sport’s entrenched masculinist culture remains a challenge for women hoping to make their mark. In addition, the work of a jockey is dangerous as horses are pushed to their limits and sometimes injured in a race.

During the early days of modern racing, it was common to refer to a winning horse without specifying the rider, or at least to not include their names in contemporary accounts. This was partly because, when races consisted of 4-mile heats and the winning of two required to be adjudged victorious, a rider’s judgment and skill was not so crucial to success.

As dash racing (one heat) came to be the standard for many races, the jockey’s skill and judgment were much more important as a means of coaxing an advantage from his mount. This led to a greater degree of personal identification between horses and their followers, and Seabiscuit was a prime example of the crowd-pleasing horse that fans cheered by name.

In general, the winning times of elite races in both horse and human athletes have improved over time. However, the improvements in time for both men and horses appear to have reached their physical limit in recent years – see the progressively flattened curves in Fig. 2. Moreover, the analysis of standardized residuals in these races suggests that unusually slow times were more common than unusually fast ones.