Reining is a western riding competition for horses where the riders guide the horses through a precise pattern of spins, stops and circles. All the work is done at the lope (a slow, relaxed version of the horse gait more commonly known worldwide as the canter), or the gallop (the fastest of the horse gaits). Reining may be described as a Western form of dressage riding, because it requires the horse to be responsive and in tune with its rider, who's aids should not be noticeable, and judges the horse based on its ability to perform a set pattern of movements. The horse should be willingly controlled or guided with little or no apparent resistance and dictated to completely. If the horse pins his ears, conveying a threat to his rider, runs sideways, refuses to go forward, wrings his tail in irritation, bounces his rear, or displays an overall poor attitude is not being guided willingly, and will be judged accordingly. The reining pattern includes an average of eight to twelve movements which must be executed by the horse.
The patterns will require the following movements:
- Circles: the horse must perform large and fast circles at a near-gallop. They must be able to perform slow and smaller circles at a lope. The circles should be perfectly round, with the rider in completely control of the the pace of the horse. A noticeable change in speed should be seen as the rider changes from the larger circle to the smaller circle. Most circles incorporate changes of direction that require a flying lead change.
- Flying lead change: the horse changes its leading back and front legs at the lope mid-stride, which is during the suspension phase of the gait. The horse should not break gait or change speed. Although completing a change at speed can improve one's score, accuracy is the most important factor to a judge. A horse that takes more than one stride to complete the change, changes too late, changes too early, or changes only the front feet and not the back feet will be penalized.
- Rundown: the horse gallops or "runs" along the long side of the arena, at least 20 feet from the rail or fence. A rundown is a required movement prior to a rollback and a sliding stop to the designated direction.
- Sliding Stop: the horse accelerates to a gallop and then suddenly comes to a complete stop, planting its back feet in the footing and allowing its back feet to slide several feet, while continuing to let its front feet "walk" forward. The back should be raised upward and its hind legs should come well underneath. A particularly powerful stop may cause some dirt to fly which can then cause a cloud of dust. The horse's position should remain the same and the movement should finish in a straight line.
- Back or Backup: the horse backs up quickly for at least 10 feet. The horse must be able to back in a perfectly straight line, and stop when asked to stop and hesitate briefly before its next movement. It will be judged on how quick, straight and smooth the line is.
- Rollback: the horse should immediately without any hesitation, be able to performs a 180-degree turn after stopping from a sliding halt and then should immediately go forward again into a lope. The horse must turn on its hind legs, bringing its hocks well under, and the motion must be continuous without hesitation.
- Spins or Turnarounds: This will begin from a complete standstill. The horse spins 360 degrees or more in place around its stationary inside back leg. The back pivot foot remains basically in the same location throughout the entire spin, although the horse may still pick it up and put it down as it spins. The spins are judged on smoothness, correctness, and cadence. Speed adds to the difficulty but it can also improve the score if the spin is done correctly. A pattern requires at least one set of spins in each direction. If the horses don't stop the spin in the designated place they will be penalized for under or over spinning. The term Pivot is sometimes used to describe a turn on the hind legs of up to 360 degrees where the horse has to keep a rear pivot foot in place. In 4-H competition, pivots of 90, 180, or 360 degrees can be used in pattern classes to introduce youth riders to the concepts of reining.
- Pause or Hesitate: The horse will be asked to stand still for a few seconds to "settle" between certain movements in the reining pattern, normally after spins. Pauses are not judged as a movement as such, but a horse that behaves with impatience or is ill-mannered when asked to wait will be penalized.