What are the keys to a rundown and slide-stop in a reining pattern?

The rundown and sliding stop is the signature maneuver of reining — it's what the sport is built around and what the crowd comes to see. But what looks like pure speed and athleticism from the rail is actually the product of incredibly precise horsemanship, and the stop itself is only as good as everything that happened in the rundown leading up to it. Get the rundown wrong and the stop suffers, no matter how talented your horse is. The rundown begins the moment you leave your last circle or maneuver. Your horse needs to be straight — not drifting toward the fence, not cutting to the center — and driving forward from his hindquarters with energy. A horse that's strung out on his forehand going into the stop cannot slide. He has to be collected and driving from behind, because the slide is produced by the hind end, not the front. Speed needs to build gradually and deliberately. Don't leave the end of the pen already at full throttle — let your horse rate up through the pen, find his stride, and hit his maximum speed in the middle third of the rundown. That gradual build gives him time to get organized underneath himself and arrive at the stop with his hind end engaged rather than strung out and scrambling. The stop cue itself should be quiet — a deep seat, a soft whoa, and a light hand. Screaming the cue or snatching the reins produces a braced, choppy stop every time. The horse that's been properly prepared will respond to a whisper because the rundown set him up to succeed. Make the stop inevitable by the time you ask for it, not something you have to force out of him at the last second.