How does dressage improve the horse's long-term soundness?

Correct dressage training improves the horse's long-term soundness through the specific muscular development, improved biomechanics, and better weight distribution that systematic gymnastic work produces — changes that reduce the mechanical stress on specific structures and distribute loading more evenly across the horse's musculoskeletal system than an untrained horse's natural way of going. The most significant long-term soundness benefit of correct dressage training is the shift of weight from the forehand toward the hindquarters that progressive collection produces. Horses naturally carry approximately sixty percent of their weight on their front legs, and the front legs bear the additional impact of a rider's weight without the gymnastic development that redistributes this load. Correct dressage training gradually develops the hindquarters' carrying capacity, shifting the weight distribution toward the haunches and reducing the mechanical stress on the front feet, coffin joints, and fetlock joints that bear the brunt of the forehand-heavy horse's loading. The muscular development that dressage produces also directly supports the horse's joints — particularly the back, sacroiliac, and hind limb joints — by developing the muscles that stabilize these structures and reducing the joint's direct loading. A horse with a well-developed topline, strong hindquarters, and good abdominal musculature carries itself more efficiently and places less stress on its passive structures — ligaments, tendons, and joint capsules — than one that relies on passive structures rather than active muscle to support its posture and movement. Classical trainers have consistently observed that correctly trained horses remain sound and competitive far longer than those trained incorrectly, with many classical horses working productively into their late teens and twenties — a practical demonstration of the long-term soundness benefits that correct gymnastic development produces.