Usually, rushing results from one of two causes: The horse just genuinely loves to jump and is overeager about the task, or he’s been poorly trained and is frightened, seeking to ”get it over with as fast as possible.” It’s easier to settle horses who love jumping too much than it is to calm the nerves of horses who’ve been frightened.
The most basic exercise to develop your horse’s understanding of jumping and trust in you is to place rails on both sides of a crossrail or vertical (2 to 3 feet). Each rail should be 8 to 9 feet from the jump, depending on your horse’s size and stride, and they can be on the ground or set a couple of inches off the ground as cavaletti. Trot rhythmically and softly to the jump and soften your hands as you reach the first rail, allowing him to jump and figure it out. Resume your rhythmic trot on landing and keep trotting a circle over the fence, until he settles. Trot it from the other direction until that’s quiet, too.
You’ll likely want to repeat this exercise in several sessions. The next step is to move the rails 1 to 2 feet farther from the jump to 10 feet and canter over the rails and the jump, quietly and rhythmically.
If the horse bolts particularly strongly before or after the jump, ride forward to the walk or halt as quickly as possible after the jump, using strong and insistent aids as quietly as possible. Then resume the rhythmic trot. You have to instruct the horse that rushing or bolting is the wrong answer and then show him that the correct answer is to maintain his rhythm before and after each fence.
Avoid hitting the horse with a whip or punishing him severely with the bit or spurs, because you don’t want him to associate jumping with discomfort. You don’t want him to learn to avoid them. But you can’t simply let the horse run off. It’s a fine line, and it’s where patience comes in.
Once you’ve succeeded at this exercise, move on to the second, by removing the ground rails and trotting over the jump in the same rhythmical circle or figure-eight pattern. Focus on keeping the rhythm with your half-halts, making a smooth transition to trot as soon as possible after the jump. You want to keep riding as calmly and nonchalantly as possible.
Once your horse is trotting quietly over fences (this will likely take several sessions), practice cantering him over a relatively small fence or series of fences in a circle or figure-eight. Keep thinking calm thoughts.
Gymnastic grids provide a third excellent exercise for rushers, because a series of fences usually makes them slow down to look at what’s in front of them. Gymnastic lines also encourage — even force — horses to jump correctly, to use their backs and their butts.
Remember to let the horse jump, to allow him make mistakes and figure out what works and what doesn’t. Ride through this line with a soft or even loopy rein.