DAP (diagonal advanced placement)

The following article was written by Gigha Steinman, December 2005. 

Originally written as a short, informal article, it has since been copied and reprinted

many times and has appeared on an assortment of dressage websites and blogs.

Diagonal advanced placement, or DAP, can be found at the trot and canter.  The USDF’s Glossary of Judging Terms defines it as being when the “hooves of a diagonal pair of limbs (in trot or canter) do not contact the ground at the same moment.”

The trot has always been thought of as a two beat gait, with the diagonal pairs of legs landing and taking off together (with a moment of suspension between.) However, closer analysis using photography and stop action video has shown that the diagonal pairs do not always land together, resulting in what is referred to as dissociation or DAP.  When the hind leg of the diagonal pair touches down before the diagonal foreleg, it is known as positive dissociation or positive DAP.  When the foreleg of the diagonal pair touches down before the diagonal hind leg, it is known as negative dissociation or negative DAP.

Hillary Clayton was one of the pioneers in the study of DAP, as well as Dr. Mikael Holmstrom, although others have also done similar research.  Using photography and stop action video, it is easy to analyze all but the most subtle dissociation (DAP), if one knows what to look for.

Study has shown that positive DAP is desirable in dressage horses.  Positive DAP horses are thought of as being “more uphill” in their movement.  As David Collins writes, “consistent with the findings in Dr. Clayton’s article, I observed that judges seemed to choose horses that showed positive dissociation of the diagonal pairs in trot and canter.”  He adds, “it is apparently a competitive advantage when the front hoof in a diagonal pair touches down slightly after the hind hoof [positive DAP].  This seems to be true at all levels of dressage.” (Dressage Today, December 2005.)  Research on DAP was also done by Dr. Mikael Holmstrom, in the 1980’s, showing that judges award higher gaits scores to horses exhibiting positive DAP at trot.  (When people refer to DAP in dressage horses, it is positive DAP to which they are usually referring.)

Negative DAP is almost universally considered undesirable in dressage horses.  In order to be landing with negative dissociation, these horses are carrying too much weight on their forehand, or are being lazy or restrained by the rider’s hand.  As Hillary Clayton writes, “the fore hoof is more likely to contact the ground first [negative DAP] when the horse is on the forehand with the withers down.”  (Dressage Today, October 2005.)   Research has shown successful upper level horses with negative DAP, but the resounding consensus remains that positive DAP is the more desirable trait.  (Speculation might say the negative DAP horses which are successful are successful in spite of the negative DAP, not because of it.  Further speculation might say the negative DAP would be diminished or even eliminated with further training.)

Some people question whether or not DAP should be considered an gait impurity.  DAP, however, cannot be seen with the naked eye.  (It has been further suggested that DAP does become a gait impurity when it reaches the point that it can be seen with the naked eye.)  Some complain that judges should mark down for DAP, which seems like an unrealistic suggestion, since DAP by definition cannot be seen by the naked eye.   Hillary Clayton says, although we cannot see positive DAP with the naked eye, “we are able to see other aspects of the gait associated with this feature, such as the uphill movement and elevation of the forehand”, and these are desirable qualities in a dressage horse.  (Dressage Today, October 2005.)  Again, it is this uphill look which in part makes positive DAP desirable.  Unless the dissociation is so extreme that it can be observed without the aid of technology, it really cannot be considered a gait impurity. 

Positive DAP also refers to the diagonal pair in the canter.  Thought of as a three beat gait, the canter is as follows:  outside hind, inside hind and outside fore (diagonal pair) together, inside fore.  In positive DAP (dissociation) the hind leg of the diagonal pair will land before the diagonal foreleg.  In negative DAP (dissociation) the foreleg of the diagonal pair will land before the diagonal hind leg.

Positive DAP at canter is usually associated with either a very collected canter in which the front end is elevated, or with the canter pirouette.  The 2005 6-year-old Young Horse World Champion Florencio 2 caused a stir when he first won the World Championships for Young Horses as a 5-year-old, scoring the only perfect 10 for his canter, which showed an extreme amount of positive DAP.  As a 6-year-old he again scored a 10 for his canter, which again was the only 10 awarded (as of 2005) at the competition (the World Championships for Young Horses.)

DAP can be a natural quality a horse possesses from birth, or it can be the result of training.  Training can further increase or decrease the amount of DAP a horse exhibits.  Correct training will increase the horse’s ability to collect and carry himself in better self carriage, which is believed to increase the amount of positive DAP a horse will exhibit. 

It is believed that positive DAP effects the take-off phase of the trot stride as well as the landing-phase, although the precise correlation is unknown.  Assuming that the legs are traveling at the same speed, a horse which lands in positive DAP (hind leg first) will also take off hind leg first.  Depending on how much the horse loads the hind leg, it may slow the hind leg down some (to put the take-off of the hind leg closer to the take-off of the diagonal foreleg), but then this would result in the legs not traveling at the same speed, and so some uncertainty exists. 

Little research has been done on the effect of DAP on the take-off phase of the trot stride, and little if any of it is easily accessible to the general public.  Careful study of the footfalls of positive DAP horses does seem to indicate, however, that these horses are inclined to take off with the hind leg first, just as they landed with the hind leg first.  (This is study which can be easily replicated with high speed photography and/or stop action video.)  It also appears the time lapse between when the hind leg lands and then the diagonal foreleg lands is often a greater measurement than the time lapse between when the hind leg takes off and then the diagonal foreleg takes off.  This would indicate that the legs do begin to synchronize themselves somewhat upon landing.  Also, positive DAP horses which are moving forward with more impulsion (lively working trot, medium trot, extended trot) seem more prone to take off early with the hind leg, so that the measurement of when the hind leg lands and then the diagonal foreleg lands more closely matches the measurement of when the hind leg takes off and then the diagonal foreleg takes off.  Horses in greater collection seem to have a more synchronized take-off, with less of a time lapse on take-off than exhibited in the landing phase.  From this, one might hypothesize that it is because of the increased loading of the hind leg, allowing the front leg to “catch up” somewhat before take-off.  All of this is based only on preliminary research and speculation, however, and further study would be needed to ascertain the precise correlation between landing and take-off in the positive DAP horse at trot. 

It is believed positive DAP has no effect on the take-off at the canter.

With preliminary study indicating that the positive DAP horse does take off sooner with the diagonal hind leg, it means that there is in fact a moment during the trot stride when the horse’s weight is passing over the foreleg only, just as there is a moment during the trot stride when the horses weight is solely on the hind leg.  This is another observation meriting further study, especially to establish whether or not this is believed to have any effect on soundness long term. 

About the author:  Gigha Steinman is a successful FEI-level dressage trainer and instructor.