How do you develop a horse that is genuinely forward thinking versus one that is dull to the leg?

A forward-thinking horse is one that moves freely and willingly from a light leg aid, maintains its pace without constant encouragement, and feels to the rider like it wants to go forward. A dull horse requires increasing leg pressure to produce the same forward response, falls behind the leg whenever the rider's leg is passive, and gives the overall impression of reluctant rather than willing movement. The distinction is significant because a dull horse requires the rider to work continuously to maintain pace, which consumes attention and energy that should be directed toward the quality of the work. Dulling to the leg most commonly develops when a horse is ridden with continuous, nagging leg pressure — a rider whose leg is always on, squeezing or bumping constantly, teaches the horse to tune out the leg because it is never absent. The horse cannot distinguish the moment the aid is applied from any other moment because the leg is never truly away. The correct approach requires the rider to apply a light leg aid and immediately release it, and if the horse does not respond, to apply a stronger aid — including a tap with the whip if necessary — and then immediately release again when the horse responds. This sequence, applied consistently, teaches the horse that the leg is sometimes present and sometimes absent, which makes the moments it is present meaningful. A horse that has become dull to the leg requires a deliberate retraining program in which the rider uses the lightest possible aid, reinforces it sharply and immediately if not answered, and releases completely when the horse responds — repeating this sequence consistently until the horse's threshold of response has been rebuilt to a light, attentive level.