From Academic Kids
The fundamental purpose of Dressage (a French term meaning "training") is to develop, through standardized progressive training methods, a horse's natural athletic ability and willingness to perform, thereby maximizing its potential as a riding horse. Although the discipline has its roots in classical Greek horsemanship, dressage was first recognized as an important equestrian pursuit during the Renaissance in western Europe. The great European riding masters of that period developed a sequential training system that has changed little since then and is still considered the basis of modern dressage.
Early European aristocrats displayed their horses' training in equestrian pageants, but in modern dressage competition, successful training at the various levels is demonstrated through the performance of "tests," or prescribed series of movements within a standard arena. Judges evaluate each movement on the basis of an objective standard appropriate to the level of the test and assign each movement a score from 0 to 10-zero being "not executed" and 10 being "excellent." A score of 9 (or "very good") is considered a particularly high mark.
There are two sizes of arenas: small and standard. The small arena is 20 meters by 40 meters, and is used for the lower levels of dressage and 3-day eventing dressage. The standard arena is 20 meters by 60 meters, and is used for upper-level tests. Dressage arenas have a lettering system around their outside in the order (clockwise) A-K-E-H-C-M-B-F (small arena) and A-K-V-E-S-H-C-M-R-B-P-F (standard arena). At the start of the test, the horse enters at A. There is always a judge sitting at C (although for upper-level competition, there is generally more than one judge at a second or third place around the arena). The invisible letter X is always in the center of the dressage arena.
The dressage arena also has a centerline (from A to C, going trough X in the middle), as well as two quarter-lines (halfway between the centerline and long sides of each arena).
The dressage tests performed at the Olympic Games are those of the highest level-Grand Prix. This level of test demands the most skill and concentration from both horse and rider.
Gaits and movements performed at this level include collected and extended walk, trot, and canter; trot and canter half-pass (almost a sideways movement); passage (a slow-motion trot); piaffe (a "trot in place"); one and two tempi changes (where the horse appears to skip as it changes leads in the canter); canter "zigzags"; and pirouettes (a 360-degree circle, in place, at the canter).
Tests ridden at the Olympic Games are scored by a panel of five international judges. Each movement in each test receives a numeric score and the resulting final score is then converted into a percentage, which is carried out to three decimal points. The higher the percentage, the higher the score.
Olympic team medals are won by the teams with the highest, second highest, and third highest total percentage from their best three rides in the Grand Prix test.
Once the team medals are determined, horses and riders compete for individual medals. The team competition serves as the first individual qualifier, in that the top 25 horse/rider combinations from the Grand Prix test move on to the next round. The second individual qualifier is the Grand Prix Special test, which consists of Grand Prix movements arranged in a different pattern. For those 25 riders, the scores from the Grand Prix and the Grand Prix Special are then combined and the resulting top 15 horse/rider combinations move on to the individual medal competition-the crowd-pleasing Grand Prix Freestyle.
For their freestyles, riders and horses perform specially choreographed patterns to music. At this level, the freestyle tests may contain all the Grand Prix movements, as well as double canter pirouettes, pirouettes in piaffe, and half-pass in passage. For the freestyle, judges award technical marks for the various movements, as well as artistic marks. In the case of a tie, the ride with the higher artistic marks wins.  (http://www.usdf.org/AboutUs/DescriptionOfDressage.asp)
Apart from competition, there is a tradition of Classical Dressage, in which purists pursue the tradition of dressage as an art form, for its own joy and beauty. Dressage is also a part of the Portuguese and Spanish bullfighting exhibitions. The traditions of the Old Masters who originated Dressage are kept alive by the Spanish Riding School in Vienna, Austria and the Cadre Noir in Saumur, France.
Breeds commonly used for competitive dressage are normally in the warmblood category, as these breeds have the vigorous, extended movement and strength necessary for the sport. However, Dressage is an egalitarian sport in which all breeds are given an opportunity to compete successfully. Iberian horses such as the Andalusian, Lusitano and Lippizanner are most popular among practitioners of Classical Dressage. These breeds excel in the collected movements of Classical Dressage.
- US Dressage Federation (http://www.usdf.org/)
- Spanish Riding School (http://www.spanische-reitschule.com/english/welcomee.html)
- Classical Dressage (http://www.classicaldressage.com)
- Classical Dressage Notebook (http://www.homestead.com/ridebetter/index.html)
- British Dressage (http://www.britishdressage.co.uk/)
- Dressage Daily (http://www.dressagedaily.com/)
- Dressage Unlimited (http://www.dressageunltd.com/)de:Dressurreiten