How does dressage benefit a jumping horse?

Dressage training benefits jumping horses in ways that directly address the specific demands of approaching, jumping, and landing fences safely and effectively — benefits so well recognized that flatwork and dressage training are universally incorporated into the training programs of serious show jumpers and eventers at every level. The most fundamental benefit is the jumping horse's balance and adjustability between fences: a horse that can lengthen and shorten its stride while maintaining balance and rhythm — skills developed through dressage transitions and pace adjustments — can be presented to each fence at the optimal distance and canter quality regardless of what the preceding fence's landing produced. A jumper that has no adjustability in its canter is at the mercy of whatever distance the fence produces, while one with genuine dressage training can lengthen to a long distance, shorten to a short one, and maintain balance through related distances as the course demands. The suppleness and throughness that dressage develops improves the jumping horse's scope and expression over fences — a horse that is through and supple bascules more completely over fences, uses its back more freely, and uses its hindquarters more powerfully than one that is tense and stiff, because the same back suppleness that produces throughness in dressage produces the bascule that effective jumping requires. The lateral suppleness from dressage work — shoulder-in, leg yield, half-pass — develops the jumping horse's ability to jump on angles, to adjust its track to a fence, and to handle related distances that require lateral correction. Event horses require dressage as a specific competitive phase, and the dressage scores that distinguish even very similar-jumping horses in eventing competition reflect the real training difference that systematic dressage development produces.