How do I fix a speed event horse that has developed pattern anticipation problems?

Pattern anticipation — where the horse begins to run to its practiced positions before the rider asks, turns before the correct point, or accelerates through portions of the pattern without guidance because it has memorized the expected sequence — is one of the most common training problems in speed events. A horse that is anticipating the pattern is not responding to the rider; it is running its memory of the pattern. The root cause of pattern anticipation is almost always excessive repetition of the complete pattern at competition speed. A horse that runs the same pattern in the same direction at the same pace in the same arena day after day develops a strong conditioned response to the visual and spatial cues of the course. The correction begins with breaking the pattern's predictability. Running only one or two elements of the pattern rather than the complete pattern, changing the direction of the run, working the individual obstacles as separate exercises rather than a sequence, and avoiding the complete pattern for an extended period all disrupt the conditioned response without punishing the horse for the behavior that training inadvertently reinforced. When the complete pattern is reintroduced, varying the approach speed, stopping and standing at different points in the pattern, and walking through portions that are typically galloped prevent the horse from re-establishing the same anticipatory response. The goal is a horse that responds to the rider's cues throughout the run rather than running its own program.