A laid back or sloping shoulder is common in horses. It mostly affects horse sports such as jumping, racing, cutting, reining, polo, eventing, driving, and dressage, and increases endurance.
The horse which has an oblique angle of shoulder (measured from the top of the withers to the point of shoulder) with the withers set well behind the elbow makes for a smooth, comfortable ride. A laid back or sloping shoulder often accompanies a deep chest and high withers.
The horse with a sloping shoulder has a long shoulder blade to which attached muscles effectively contract and so increase the extension and efficiency of stride. It distributes muscular attachments of the shoulder to the body over a large area, decreasing jar and preventing stiffening of the shoulders with impact.
The horse has an elasticity and free swing of its shoulder, enabling the extension of stride that is needed in dressage and jumping. A long stride contributes to stamina and assists in maintaining speed.
The longer the bones of the shoulder blade and arm, the easier it is to fold legs and tuck over fences. The laid back scapula slides back to the horizontal as the horse lifts its front legs, increasing the horse’s scope over fences.
A sloping shoulder has better shock-absorption and provides a comfortable ride because it sets the withers back, so a rider is not over the front legs.