The Horse in motion. "Abe Edgington," owned by Leland Stanford; driven by C. Marvin, trotting at a 2:24 gait over the Palo Alto track, 15th June 1878 / Muybridge.

In harness racing, a Standardbred horse pulling a light two-wheeled vehicle called a sulky. Harness racing horses are of two kinds: - the pacing horse or pacer, that moves both legs on one side of its body at the same time; - the trotting horse, or trotter, strides with its left front and right rear leg moving forward simultaneously, then right front and left rear together. Harness racing is ancient. Assyrians trained horses to draw chariots, to use them in a war, a sport of hunting. Homer mentioned of the chariot race in the Iliad. Four-horse hitch chariot races took place in the Olympic Games of the 7th century bc. Chariot racing came into great prominence in Rome. A perfect site for chariot racing Circus Maximus, that could hold 200,000 spectators, was built in Rome. In the reign of Augustus (27 bc–ad 14), there were 12 races a day; by Flavius’ reign (69–96), the number rose to 100, from daybreak until sundown, the length of races being shortened to accommodate the larger number. The chariot disappeared as a military vehicle and chariot racing ended with the fall of Rome in the 4th century; modern harness racing did not begin to evolve until early in the 19th century. In the early 19th century there were trotting tracks in the United States. Yankee trotted a mile over the track at Harlem, New York, in 1806, Boston at the Hunting Park track and in Philadelphia in 1810. In 1830s harness racing thrived at county fairs. In 1871 the Grand Circuit, the Quadrilateral Trotting Combination, was established and grew from 4 to 23 tracks. In 1879 the Standardbred horse was established in the United States.

Locomotion was a popular method of making a series of consecutive images for artistic and scientific purposes.