How Fast Can a Horse Run: The Science of Horse Racing

Few sights beat two horses dueling down the stretch, flashing by fans in a split second as they hurtle at top speed toward the wire. We marvel at their abilities and celebrate those who break a record, holding up times like 2:24 as hallmarks of the greats. From the sport’s earliest days, breeders and owners have been pairing sires and dams together to create a horse that can finish faster than their competitors, a champion with the right physical talents to win.

Whether they pull a sulky, run a long distance, or sprint over a short quarter mile, three breeds are the stars of the sport we all love, but, of the three, who is the fastest and why? Keep reading to learn more about the captivating world of equine speed and discover just how fast a horse can run.

An Origin Story

Horses were first domesticated at least 6,000 years ago, with archeologists pinpointing the western part of the Eurasian Steppe, which covers what we now know as Ukraine and western Kazakhstan, as the likely point of origin. No doubt, the first conversation about who had the fastest horse happened the next day. Over the centuries since, the pursuit of a faster and stronger breed of horse has been an aim of sportsmen all over the world.

To that end, three Arabian stallions, the Darley Arabian, the Godolphin Arabian, and the Byerly Turk, were imported from the Middle East to England and bred to native-bred mares for the purposes of creating a new breed that could carry a rider at a sustained speed over a distance. Over the last three centuries, breeders have been purposefully selective in pairing stallions and mares to produce a horse that can sustain its speed over distances five furlongs and beyond.

Alternately, the other two breeds with racing of their own, harness racing's Standardbreds and Quarter Horses, have origins that tie in with the Thoroughbred but have developed into separate breeds over the centuries. Standardbreds originate with the English Thoroughbred stallion Messenger, who was imported to the United States in 1788, and then crossed with Morgans and others to produce horses that were fast trotting or pacing.

Quarter Horses grew out of crosses between Thoroughbreds and the descendants of the horses the Spanish brought over during the colonial era. During the early years of the American colonies, cleared land was at a premium so races were often conducted over shorter distances, like a quarter of a mile, which led breeders to seek horses that could sprint. Later, as more formal racecourses developed, breeding for longer distances gave rise to the American Thoroughbred, able to sustain their speed over the ground favored by their breeders and owners.

But of these three breeds currently competing over racetracks across America, who truly is the fastest and why?

A Question of Speed

As The Science of Horse Racing has explored previously, horses have three basic gaits: walk, trot, and canter, with the gallop being a much faster version of the latter. The pace, the other gait seen in Standardbred racing, is similar to the trot, but uses the legs differently; whereas a trot moves the legs in diagonal pairs, the pace moves the two legs on the same side in tandem, which makes pacing much faster than trotting. Quarter Horses and Thoroughbreds’ competitive gait is the gallop, but one breed achieves a top speed far superior to the other.

Each of these gaits has its average speed for all horses, independent of breed.

The top speed for a Standardbred averages around 30 miles per hour, with the fastest recorded speed of 46.5 miles per hour achieved by Western Dreamer in the late 1990s. Compare that with the basic average trotting speed of eight miles per hour and we get a clear perspective on just how fast a Standardbred is!

The other two racing breeds, Thoroughbred and Quarter Horse, are both bred for speed at a gallop, but they have developed independently based on the distances each is bred for. Quarter Horses must reach their top speed in a few strides since their races are only two furlongs or 440 yards. The average Quarter Horse races between 45 and 50 miles per hour, with the fastest speed ever recorded at 55 miles per hour.

Thoroughbreds, conversely, also gallop but over longer distances, with most races starting at five furlongs and topping out around 2 1/2 miles. The average speed for that breed is 40 miles per hour, while Drip Brew recorded the fastest quarter of a mile ever, :19.97, in 2020, according to Equibase. His top speed for that distance peaked at just over 45 miles per hour.

Why is a Quarter Horse so much faster than a Thoroughbred? In short, it comes down to their anatomy. Quarter Horses are shorter and stockier with a broad chest and a well-muscled hind, designed to achieve top speed within a short distance; Thoroughbreds are lean and athletic with slimmer torsos and longer legs, their physiques built for sustaining their speed over longer distances. Thoroughbreds are taller too, 15.2-17 hands, which means a longer stride than the shorter Quarter Horse, which stands between 14-16 hands.

Fast and Fun For All

Just like humans, some horses will be faster than others. Not every horse can be a sprinter, but certainly, racing has opportunities for all horses to find a distance and surface where they shine. From Standardbreds hitched to a sulky to Quarter Horses flashing down the track, each of these racing breeds has their top speeds, with centuries of mindful breeding cultivating the abilities that each has to offer. The best part of it all is the thrills that each brings to racing fans everywhere.