How do you develop a young horse's balance and straightness under saddle?

Balance and straightness are qualities that develop progressively throughout a horse's training and are directly related to the horse's physical development and muscular strength. A young horse under saddle is naturally crooked — it has a naturally stiffer side and a naturally more flexible side, and it tends to travel with its hindquarters slightly off the track of its front feet rather than stepping straight through. This natural crookedness must be addressed systematically through training rather than ignored, because a horse that travels crooked is developing uneven muscular strength, placing uneven load on its joints, and cannot develop true collection or the more advanced lateral movements that require straightness as a foundation. Developing straightness begins with the rider learning to feel the horse's crookedness — which hindquarter is falling in, which shoulder is falling out — and applying corrective aids that address the specific deviation rather than the general issue. Riding shoulder-fore — a slight positioning of the horse's shoulders to the inside so that the hind feet track in the direction of the front feet — is the most commonly used exercise for developing straightness in a young horse. Large circles develop the horse's ability to bend equally in both directions and reveal asymmetries in suppleness that need to be addressed. Work on both reins for equal amounts of time, combined with systematic attention to the horse's straightness in transitions and along straight lines, develops the even muscular development and symmetrical movement that straightness requires. A horse that travels genuinely straight, with its hind feet following the track of its front feet and its body moving in a single consistent line, is a horse whose balance and strength are developing correctly.