 Only after 1952, as mechanization of warfare reduced the number of military riders, were civilian riders allowed to compete.Equestrian is the only Olympic sport in which animals compete with humans, and is one of four sports in which the genders compete against each other, the others being some sailing divisions, mixed doubles division in tennis and the mixed doubles division of badminton.The rules for Olympic equestrian competition are set by the Fédération Équestre Internationale, the international governing body for equestrian sports.