Quarter horses are mostly used for barrels cause they were bred to be fast for a short period of time,theyre called the "quarter horse" because theyre the fasts horse,but only for about a Quarter of a mile,theyre also Americas most popular breed,so thats another reason,they have strong hind ends and are good for cutting,and theyre not very small usually,so theyre good for roping,most of the rodeo events need a fast horse,so the Quarter horse fits the bill.