How do I develop correct bend and flexion through both directions for English pleasure?

Correct bend through both directions of the arena is a fundamental requirement of an English pleasure horse that is often underdeveloped in horses trained primarily through straight-line work. A horse that bends correctly through turns and circles — with its spine following the arc of the turn, its inside hind leg stepping under toward the track of the inside front, and its neck flexing to the inside without excessive neck bend that disconnects from the body — is a horse that moves through both directions of the arena with equal quality and straightness. Developing correct bend begins with lateral exercises at the walk that ask the horse to move its entire spine along a curved path rather than only its neck. Circles, spirals, and serpentines ridden with deliberate attention to the horse's body position — using the inside leg to encourage the barrel to swing outward and the inside hind leg to step under, and the outside rein to prevent the outside shoulder from falling out — develop the muscular suppleness that correct bend requires. Many horses have a naturally easier direction for bend and a more difficult one, and the training program must address both rather than simply working the easy direction and avoiding the difficult one. Extra time and extra patience spent developing the difficult direction gradually bring it closer to the quality of the easy direction, and a horse that is equally supple in both directions is more competitive in a class where it must demonstrate equal quality going both ways around the arena. A horse that can ride a genuinely round circle with consistent bend throughout is far along in its lateral development compared to one that merely points its nose to the inside while its body travels straight.