Why does my reining horse get dull?

A reining horse becoming dull — losing responsiveness to the leg, becoming heavy in the bridle, requiring more pressure to produce the same responses it previously gave to lighter cues — is the predictable result of training that has overused the aids without adequate release, drilled repetitively without rewarding correct responses, accumulated fatigue without sufficient recovery, or confused the horse through inconsistent cues that required more pressure over time to overcome the confusion. The most common and most insidious cause is asking harder rather than asking clearer when the horse does not respond correctly. A horse that does not move off the leg gets stronger leg, and then stronger leg, and eventually spurs — and learns over time that it does not need to respond until the pressure reaches a specific level that has become the new threshold. This is the training pattern that creates dullness most reliably, and it is extremely common because it feels like the correct escalation of pressure when it is actually the installation of a higher pressure threshold. The correction is the opposite: go back to asking lightly, accept the smallest try at the correct response as sufficient reward for that moment, and release immediately at that try. Over repetitions the horse's threshold for response returns to a lighter level because light pressure is now reliably the cue that produces reward. Overuse of cues without release creates a similar dullness through a different mechanism — if the leg is always on, the leg means nothing specific and the horse ignores it. Fatigue and confusion produce dullness that looks like resistance but resolves when the horse is given rest and clarity. The most practical diagnostic for dullness is to reduce the pressure being used and see whether the horse responds to less — if it does, the threshold has been trained up and needs to be rebuilt from a lighter starting point.