Reining is a horse sport described below.

As defined by the 2008 NRHA Handbook (see below*):

Reining:

To rein a horse is not only to guide him, but also to control his every movement. The best reined horse should be willingly guided or controlled with little or no apparent resistance and dictated to completely. Any movement on his own must be considered a lack of control. All deviations from the exact written pattern must be considered a lack of or temporary loss of control; and therefore, a fault that must be marked down according to severity of deviation. After deducting all faults set here within, against execution of the pattern and the horse's overall performance, credit should be given for smoothness, finesse, attitude, quickness, and authority of performing various maneuvers, while using controlled speed which raises the difficulty level and makes him more exciting and pleasing to watch to an audience.

Scoring:

The scoring of reining horses is on a positive numeric scale with 70 denoting a correct performance. NRHA patterns are comprised of several distinct maneuver groups, which judges are asked to evaluate on an individual basis depending on execution as dictated by the pattern description and the rules for judging. The individual maneuvers are scored in ½ point increments from a low of -1½ (extremely poor quality) to a high of +1½ (excellent quality) with a score of 0 denoting a maneuver that is correct with no degree of difficulty. The total of the scores applied to the maneuver groups is combined with the starting score of 70 and from this gross maneuver score, any penalties are deducted to calculate the the horse's final score, which is announced after each horse works.

*The NRHA handbook, in its entirety, can be found at www.nrha.com/handbook.php. It is in pdf format, so you will need the free Adobe Reader in order to view or print it; which you can get here.