Feeling the earth shake as a mass of thundering hooves barrels down the stretch during a horse race is one of the quintessential Kentucky experiences. Horse races have also become a metaphor for business battles, as managers strive mightily to avoid a succession “horse race,” wherein several recognized candidates compete against each other to be the next chief executive officer. The term first appeared in the 19th century and has morphed over the years to refer to any close form of competition.

As with most sports, there’s a science to winning a horse race. The trainer, or jockey, is the heart of the operation; his decisions can make or break a race. One must know the horses’ personalities, their strengths and weaknesses, their training and diets. He must be able to read the crowds and respond quickly, as well as judge the speed of the track. And he must be able to inspire his charges.

Horses, especially those that run on oval tracks, take a beating. Their lower legs get a particularly vicious pounding, straining tendons and ligaments. Many need encouragement, or whipping, to keep going hard. And they’re often spooked by other competitors or even by the shadow of a rider’s head in the stall.

Some jockeys, including the famous Mike Smith, have argued that horses don’t like to run and need to be forced to do so. But the truth is that racing is not natural for horses, and a lot of work goes into making it safe and fair for them to race.

There are many other factors that contribute to a good horse race, too: the weight that each is required to carry for fairness; allowances for age and sex; and more. Adding up all of these things allows handicappers to calculate a horse’s chances of victory.

The earliest races were match races between two or three horses, with the owners providing the purse, and bets placed on the outcome. These agreements were recorded by disinterested third parties, who were known as keepers of the match book.

As the sport developed, the number of runners grew. Rules were established on who could participate, with consideration for age, sex, birthplace and previous performance. The most prestigious races are called conditions races, and offer the largest purses.

In recent decades, racehorse ownership has undergone a radical change. Where once there was typically a single wealthy tycoon to whom jockeys rode, today many horses are owned by syndicates, which divvy up shares among hundreds of people. The rise of these partnerships has democratized the sport and strengthened its bottom line.

There are still problems with animal welfare in horse racing, though. The recent passage of the Horseracing Integrity and Safety Act was a positive development. But a number of states have blocked its implementation. Meanwhile, lawsuits and legislative measures threaten to thwart reform. And the issue of doping is roiling the industry. In a sport where the most important drug is trust, doping is a serious threat to the integrity of the game.