The U.S. Trotting Association is the governing body of harness racing in the United States. Harness racing is a type of horse race in which the horse pulls the jockey in a cart behind him
Broadly, harness racing is divided into two categories, based on the horse's gait. Trotting describes a gait in which the horse moves its legs in diagonal pairs, moving its front left and rear right leg at the same time, followed by the opposing pair. Pacing is a gait in which the horse moves its legs in lateral pairs, with both right legs moving forward followed by both left. Pacing races are significantly more popular in the United States than are trotting races.