Three day events are now offered in the classic format, with endurance day, or short-format, with no steeplechase (phase B) or roads and tracks (phases A and C), the 2004 Olympic Summer Games in Athens, Greece chose the short format, due to lack of facilities, time and financing, which sparked a large debate in the eventing community whether to keep the steeplechase phase or just offer cross-country.
Today, most events are run short-format; in the United States the "classic format" remains a popular option for the Novice, and Training levels of competition at select events.
Safety regulations mean that some obstacles are now being built with a "frangible pin system", allowing part or all of the jump to collapse if hit with enough impact.
Speed is also a factor, with the rider required to cross the finish line within a certain time frame (optimum time).
A horse and rider pair can also be eliminated for going off course, for example missing a fence.
If the horses shoulder and hind-quarter touch the ground, mandatory retirement is taken and they are not allowed to participate further in the competition.
Therefore, if one movement is poorly executed, it is still possible for the rider to get a good overall score if the remaining movements are very well executed, the marks are added together and any errors of course deducted.
To convert this score to penalty points, the average marks of all judges are converted to a percentage of the maximum possible score, subtracted from 100 and the multiplied by a co-efficient decided by the governing body.
Dressage work is the basis of all the other phases and disciplines within the sport of eventing because it develops the strength and balance that allow a horse to go cross country and show jump competently.
At the highest level of competition, the dressage test is roughly equivalent to the United States Dressage Federation Third Level, and may ask for half-pass at trot, shoulder-in, travers, collected, medium and extended gaits, single flying changes and counter-canter.
Traditionally, three-day events had dressage, endurance, and show jumping.
Endurance day consisted of 4 phases: A, B, C and D.
Fitness is required as the time allowed will require a strong canter at the lower levels, all the way to a strong gallop at the higher events.