Standardbred horseStandardbred harness racing horses are so called because in the early years of the Trotting Registry, the standardbred stud book established in the United States in 1879 by the National Association of Trotting Horse Breeders, only horses who could race a mile in a standard time or better, or whose get could race a mile in standard time or better, were entered in the book.
In continental Europe all harness races are conducted between trotters. A trotter's forelegs move in unison with the opposite hind legs -- when the right foreleg moves forward so does the left hind leg, and vice versa. In Australia, Canada, New Zealand, the United Kingdom, and the United States, races are also held for pacers. Pacers' forelegs move in unison with the hind legs on the same side.
Standardbreds have shorter legs than thoroughbred race horses and longer bodies. They also are of more placid dispositions, as suits horses whose races involve more strategy and more re-acceleration than do thoroughbred races.