Harness racing use a standing start. The sulky (informally known as a "bike") is a light, two-wheeled cart equipped with bicycle wheels. The driver (not a "jockey", as in thoroughbred racing) carries a light whip chiefly used to signal the horse by tapping and to make noise by striking the sulky shaft. There are strict rules as to how and how much the whip may be used; in some jurisdictions (like Norway), whips are forbidden. For exercising or training, the drivers use what is known as a "jog cart," which is a sulky that is heavier and bulkier than a racing unit.
Horses in the Middle Ages and also clear from the change from the Roman two-field crop-rotation system to a new three-field system, which increased the cultivation of fodder crops (predominantly oats, barley and beans). Horses were also used to process crops; they were used to turn the wheels in mills (such as corn mills), and transport crops to market. The change to horse-drawn teams also meant a change in ploughs, as horses were more suited to a wheeled plough, unlike oxen. The development of equestrian technology proceeded at a similar pace as the development of horse breeding and utilisation. The changes in warfare during the