Why do jocky's ride the horese the way that they do?

Question

Why can't they sit down on the horse. To me it look very uncomfortable for both the horse and rider. Wouldn't they be putting on more weight on the back of the horse?

Answer 1

the position they use is the most aerodynamic. its not uncomfortable at all. if they sat down they would be bouncing and rolling round in the saddle, when they just crouch they arent bouncing round, and they help the horse to stay balanced. the horse carries the same weight either way, its just more comfortable for the horse if the jockey crouches

Answer 2

They keep their weight forward, the horses power comes from it's rear end. At a  gallop this is the normal position anyway if you ride English.