So you are trotting up the center line, wearing your nice dressage apparel and on your well-groomed horse. And just as you get to X, your horse does his version of a capriole and dumps you in the dirt. What set him off?
Let’s start with “the obvious suspects”—people trying to take the perfect close-up photo and hanging over the railing, small running children in the arena, flapping things (flags, blankets, papers on clipboards), and other people’s horses acting up. Now let’s get to others: remember the pigeons in the old arena at Cedar Trace? How about the blood from de-horned cattle at Freeman Arena? (You couldn’t smell it but your horse sure could!) There are some memorable ones: hot air balloons going overhead (Wuff! Chuff!), pigs next door, and the night-time lesson when the barn cat let a live rat loose in the arena and both the cat and a dog chased it under the horse’s feet (oh, please, please halt!) .
So what can you do? At a show, the management can insist that spectators keep their distance and warn people with small children to stay away from the horses. But what can you do otherwise? Start by acclimating your horse to areas outside of your covered arena. Is there a pasture where you can ride? Can you ride with somebody whose horse is a wise old-timer who will not react? If all you do is practice inside an arena (same test, same time of day, etc.,) you are setting yourself up for trouble. So do something different! Are there some trees, bushes, or maybe some jumps in your field? Do some figure S’s or pole-bending around them at your gait of choice. Will your horse hop over a tiny ditch or a mud puddle? Can you lean away from your horse to open a gate or grab something? How does your horse react to a flag, a blanket over his head, or you putting on a flappy jacket or raincoat? Can your horse back up? If you need inspiration, look up some training exercises for the western trail class. No, you do not need to ride through a pen of armadillos or a cloud from a fog machine, nor do you need to pick up a raw animal hide or shoot a pistol.
It’s a good idea to get out of a rut no matter what level you ride.
Brazos Association for Classical Horsemanship 