John Whitaker Training System. The John Whitaker Training System has been designed for use whilst lunging and helps to develop the horse's neck and back muscles. The Training System encourages the horse to work in an outline and use their hind quarters correctly which in turn teaches self carriage. The Training System includes adjustable roller, adjustable ropes and pulleys and sheepskin padding to reduce rubbing on the horse's back legs. Fully adjustable meaning it fits most horses and ponies. Read more… Instructions included.