DAP for beginners: where to land

The debate about DAP – or Diagonal Advanced Placement – is happening again on the internet. A video by long time horse breeder Barbara Schulte has been doing the rounds and is currently cause for discussion. In her video, Mrs. Schulte claims that sport horses are being bred to be hyper mobile in order to create the huge, flashy gaits favoured by dressage judges and that this causes a deterioration in the quality of the gaits. Mostly of the trot, which has ceased to be a two beat gait in that the hind legs are now slightly ahead of the diagonal front legs in every stride – also known as Diagonal Advanced Placement.

On the other side are people who believe DAP to be a good thing because it correlates positively with winning dressage scores. Dressage scores are supposedly awarded to horses who move well. The problem is that while several published, peer reviewed studies have shown that the correlation between high dressage scores and DAP is real, a single published, peer reviewed study to substantiate the claim that dressage scores correlate with good movement or even the criteria in the dressage rules has yet to be produced. In other words, we know that judges like DAP. But we don't know if they are justified in this preference. Mrs. Schulter's video can be seen on YouTube

Forgive me if the following information is too basic, but I can see in the commentary threads on social media that a lot of people still don't really understand what all this is about. So let's back up a few strides (which is still a two beat movement). Imagine having to make a trotting noise with a pair of coconut shells. Your rhythm is going to go: 1, 2, 1, 2, 1, 2 etc. That's because you already know that trot is a gait with two beats. You don't need some expert to tell you that. You also know that a horse has four legs and your natural sense of logic tells you that this means that two legs will be involved in each clip and each clop of your coconut trot. First the right hind and the left front clip. Then there is a suspension phase (unless there isn't, but you get the picture). Then the left hind and the right front clop. And then there is another suspension phase. That's a total of two beats (clip and clop) and four phases (clip, suspension, clop, suspension).

Diagonal Advanced Placement is when one of a diagonal pair of legs (for instance right hind/left front) contacts the ground before the other. Your coconut trot would (in theory) sound like this: Cl-clip, suspension, cl-clop, suspension. Usually, when it is cause for debate, people are talking about the hind leg landing first. This is because it's not really considered worth discussing whether the front leg should land first. Nobody thinks it should and so there's no controversy. The hind leg, however, is a hot potato. For decades, DAP has been actively bred for in sport horses to the point that I dare you to find a foal or youngster at any reputable auction who does not ”naturally” have it.

Obviously, breeders want to breed winners, so they are going to select winning bloodlines. Knowing that the tendency towards DAP is hereditary and that winners have it, we arrive at the conclusion that breeders are going to be breeding it and slowly changing the way horses move to fit the market which – in the case of dressage - caters to the whims of the judges. Fashion dictates what is considered healthy, and gradually, the standards of correctness slip towards the extreme. Dog and cat breeders know of this phenomenon as over-typing.

In the case of DAP, it has happened very quickly and here's why:

In 1994, the Swedish vet and scientist, Dr. Mikael Holmström published some studies in the Equine Veterinary Journal. One was entitled ”Biokinematic differences between riding horses judged as good and poor at the trot”. In this study, four approved Swedish Warmblood stallions with high scores for trot were compared with four horses with poor scores for trot. As you would expect if you are familiar with the sport horse breeding scene, the horses with the good scores were the ones who lifted their front legs up the highest. And the high speed footage of the horses revealed something else: The most impressive goose stepping correlated with Diagonal Advanced Placement.

It was an exciting time. A few years later, in 1997, Dr. Hilary Clayton showed a correlation between more pronounced DAP in collected trot and passage and higher scores at the 1992 Olympic Games in Barcelona.

I took one of Dr. Hilary Clayton's classes on dressage horse biomechanics in 2002 and remember being gobsmacked by the data from Barcelona. That there was actually a specific, hereditary movement pattern which could be used to predict performance in dressage horses just seemed like pure magic. I never stopped to question whether competitive success could automatically be assumed to indicate good balance. I never doubted that when equine scientists said things like ”uphill movement” or ”collection”, they were stating facts, set in stone. The idea that the judges could be rewarding tension and that the correlation between medals and DAP was possibly a result of such mistakes was not within my intellectual grasp.

I hurried out and told everyone about my new insights. I almost wish there were sound recordings, because I must have sounded really, really, really smart. I remember one experienced breeder of Hannoverian horses hanging on my every word as I shared the news with him that foals as young as three months old would already be displaying DAP and that this would enable him and me to pick future stars with much better accuracy.

And I wasn't the only one spreading the gospel. Federation symposia, judges' seminars and horse magazines soon lit up with articles about how ”science had shown” that horses with potential for world class piaffe and passage all had this thing called DAP, which you should therefore look for when buying a foal or a young horse or selecting a stallion. The hypothesis that DAP was a sign of a horse's natural ability to collect was repeated so often it eventually became theory. And that theory is now widely regarded as truth. Is it any wonder that almost every young sport horse now shows a fairly strong DAP? For almost 20 years, the biggest bucks have been paid for cl-clip, cl-clop. To a point where clip-clopping warmbloods are essentially extinct. The market has spoken.

Wow! Let's hope it really was a good thing that those Olympic horses in the 90s were landing with their hind legs first. Imagine if breeders had selected heavily for the trait ever since, and it turned out that DAP was actually just a symptom of tension and a decreased ability to step under with the hind legs. That would be quite embarrassing for those of us who went around telling people that DAP was great and that we should all be buying it and breeding for it. I'd want to crawl into a mouse hole.

Still, how was I supposed to know? It's not as if the classic horse manuals warned us about the significance of DAP. Except they really did. Contrary to popular opinion, Diagonal Advanced Placement was not discovered by scientists in the 1990s due to the emergence of advanced video technology. If you know a well rounded horse person, ask them to check their book shelves for Die Reitkunst im Bilde by Ludwig Koch, published in 1928.

The book describes a fault known as the ”rushed hind leg”  whereby ”the hind legs contact the ground unbent and in a dragging fashion and the hind leg is put down before the diagonal foreleg.”

Sound familiar? The description continues: ”This type is often seen in carriage horses who have been fixed too high in front in order to create the high and dazzling front leg action which impresses lay people.”

Waldemar Seunig had this to say about DAP: ”This gait is induced through false tension. Stabbing, hovering steps, braced back and a restricted neck, which ought to be stretched better forward. Due to the false posture and the forced trot, the latter becomes impure (the left hind leg pushes off before the diagonal right foreleg) which means an impure rhythm behind. The braced, non-yielding back does not swing. The collaboration of the forehand and the hind end has been disrupted. Schenkelgänger!" The description accompanies one of Seunig's own drawings, which you can see at the top of the page.

So now we know that a long time ago, horsemen knew of DAP and saw it as a symptom of tension due to a forced, unnatural head carriage. And that back then, it was associated with a type of flashy front leg movements which impressed people who didn't know what they were looking at. Was that a different type of DAP to the type the Olympic horses were showing in the 1990s? If so, isn't it a fabulous coincidence that a footfall sequence which used to denote tension due to forced riding and false collection should turn out to be the exact same footfall sequence which correlated with what rightly passed for ”good balance” and ”uphill movement” in the 1990s? The 1990s, when forced, short necks and flashy front legs were increasingly rewarded with high scores in the dressage ring. The 1990s, when it became accepted, not only to hyperflex your horse in the warm up, but also to ride behind the vertical during the actual test. That really would be some coincidence.

"But the good kind of DAP is the kind you cannot see with the naked eye. Seunig and Koch were writing of the kind you can see with the naked eye, which makes it a gait irregularity. DAP is only good as long as you can only see it in slowmotion"

That's the sort of thing you might hear people say. Okay. Let's examine the logic behind this argument. So DAP is good and more DAP is better, since the "best" moving horses in the studies of Holmström and Clayton were the ones with the most pronounced DAP. But only to a certain point. As soon as the DAP becomes visible to the human eye, it becomes a bad thing?

Which human eye are we talking about? Mine? Yours? Practically every normally sighted human can observe movement in more detail than a regular video camera, filming at 25 or 30 frames per second. And here at Epona.tv, we find that our video cameras have no problem picking up the DAP displayed by elite dressage horses. Go to YouTube and look up Nicole Uphoff's winning ride on Rembrandt from Barcelona in 1992. The video quality is really crappy, but I dare you to watch it and come back and tell me you can't see the hind leg landing first (or the neck being fixed by the reins). Fighter pilots have been known to correctly identify planes which have been shown to them for one 220th of a second. Dressage judges are famous for their inability to spot a blue tongue passing close by at six miles per hour. What is "visible to the human eye" is highly context specific. I think it's safe to say that the visible/not visible to the human eye distinction between "good" and "bad" DAP is useless.

So should we all panic about DAP? I don't think so. Even in old films of the Spanish Riding School, you can catch glimpses of DAP. God knows my own warmblood mare will DAP for Denmark whenever I push the tempo too much or botch a rein aid (or when something makes her mentally tense) But I also think that sport horse breeders and buyers (and would be pundits, myself included) should have been a bit more careful about jumping to the conclusion that DAP was a desirable trait, just because it correlated with competitive success. The winning dressage horses at the Olympic Games in Hong Kong  in 2008 were all behind the vertical in piaffe. Should we start selecting for that so that we can have foals at three months already over-bent? On second thought, don't answer that.

Is DAP caused by hyper-mobility? I don't know.

If DAP was never a sign of a horse's natural ability to collect, what was it? Before people started deliberately breeding horses to trot like that, what caused it? I'll venture a guess. I'm going to go out on a limb (pun intended) and say that this question was answered almost a hundred years ago (and probably before). I think it is what Koch and Seunig said it was. I think it is something that happens when a horse is fixed in front by the reins or his ability to track up is affected for some other reason by tension in the back.

Try going for a crawl on the floor with a tense, inverted back and see what happens to your stride length. You will want to put your knee down further back than when you crawl with a relaxed back. Now imagine you're a stiff, inverted dressage horse (though you are probably flexed at the poll). Do you want to put your hind leg down further forward or further back? Probably further back. Is that going to make your hind leg land sooner or later than it would have done? I'd say sooner because it is travelling a shorter distance. Will that make your hind leg early or late, relative to the diagonal forelimb? Yup, early. What seems counter-intuitive at first becomes obvious when you think about it. The hind leg lands first - not because it is winning some race but because it is being held back. That's why DAP is not reserved for expensive sport horses. Bailey the rehab pony who came to us so stiff and inverted he could barely move... had DAP. Lot's of horses with really sick hind legs land hind leg first. But it only looks cool when a talented sport horse does it. Stubby, hairy ponies can't seem to pull it off.

A hind leg which lands early and further back ends up standing further back - behind the front leg in a timing sense -  during the maximal loading phase. Everything about the hind leg movement is moved back, relative to the horse. So that lovely ”uphill movement” seen during the suspension phase transforms into rather a downward one as the horse begins to load the limbs. By the time the front leg is maximally loaded, the hind leg is often camped out too far to properly assist it. Even if the hind leg is still in front of the hip joint, tension prevents the horse from sinking into that hind leg, leaving him croup high and on the forehand. Perhaps that is why this type of movement was frowned upon at a time when horses were less disposable than they are today.

To illustrate, I have exported an image sequence from a video file of a dressage horse displaying DAP. I apologise for the horse being behind the vertical, but the footage was taken in 2013 at an FEI warm up arena, so it couldn't be helped. (I am going to ask Santa for a high speed camera)