Back in my horsehunting days, I did a lot of research on equine gait mechanics. What should I look for in the walk, trot, and canter? How do I distinguish the "flashy" movement from movement that indicates an animal's real potential? A friend of mine told me about diagonal advanced placement, or DAP. Hilda Gurney stressed its importance in the 1996 Centennial Olympic USDF National Dressage Symposium. She told an audience that DAP is perhaps the best single predictor of a horse's suitability for upper-level dressage.
What is DAP?
The term DAP was first introduced in 1980 by Swedish veterinarian Mikael Holstrom. Dr. Hilary Clayton at Michigan State University has also studied DAP in her research on horse biomechanics. This research has practical implications for the rider/owner.
Slow-motion analysis of the trot stride reveals that the ground contacts and lift-offs of the diagonal-limb pairs may not occur at exactly the same time; often they are slightly dissociated. An uphill horse that elevates his forehand when he moves usually touches down with his hind limb slightly before the diagonal forelimb. The above right photo is Royal Prince, a Rhodiamant son standing at Hilltop Farm. Look at the hooves about to make contact with the ground. Notice the left front is farther from the ground than the right hind--the hind will land first. This is called positive diagonal dissociation (or positive advanced placement).
Some horses make contact with the forelimb slightly before the diagonal hind limb. In the picture on the left, the camera caught this horse at a bad moment -- unbalanced, rider trying to steady him with her hands. The result is a pretty dramatic example of negative diagonal dissociation (or negative advanced placement). The left front is landing well before the right hind. Horses with negative diagonal dissociation tend to be more on the forehand than those with positive diagonal advanced placement. Depending on the circumstances, a horse may have negative DAP when they are momentarily off balance -- I suspect this is the case in the picture on the left. However, some horses just travel this way.
Assessing DAP
It's possible to assess horses with a good videotape of the horse trotting freely on a level, flat surface in an energetic but not exaggerated trot. The viewer can stop the action at the critical points in the footage to examine hoof placement. Some caveats:
- Horses in a certain stage of development (e.g., yearlings) may not show positive DAP. As they grow, their natural balance returns.
- The typical negative or positive dissociation will be far more subtle than the examples above.
- Theoretically, a very exaggerated dissociation in either direction can detract from the purit of gaits. A few purists argue that any dissociation is bad.
- Some horses will have zero dissociation (diagonal pairs land at exactly the same time.
- No one rule will hold true for all horses. The USDF reports that 1 in 5 of the horses that qualified for the 1992 Barcelona Olympics displayed negative dissociation (DAP).
RESOURCES
Diagonal Advanced Displacement blog
Don't ask me how there got to be a blog named for this topic, but there is...
Focus on discipline: Dressage from The Horse Magazine
DAP from Ridingart.com
1996 USDF symposium report from Bill Woods, Woods Dressage
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Very interesting. Makes me want to dig out videos and pictures of my horse and see where he falls in the DAP scale.
ReplyDeleteThat can be a mixed bag. I have video stills of Riley showing a strong positive DAP, but almost no articulation of the hocks. That was back when he was about 9 months and I tell myself it is only one moment in his lifetime. And I wonder about the value of staring at their feet a lot, shouldn't you look for lift in the wither, etc. But it is an interesting tool.
ReplyDeleteAnd this is why I love the horse blog community ... we learn the coolest things from each other! This is a very interesting concept that is completely new to me. So, for dressage, is it better to have positive or negative dissociation? I would have guessed positive, but the statement about 1 in 5 Olympic horses are negative confused me. Does that mean all the rest were positive, or that they were zero?
ReplyDeletePositive is definitely better, since it shows the power coming from behind and front end elevating (think popping a wheelie).
ReplyDeleteThe USDF study (to me) is the proof that despite all our best guesses and predictions, sometimes horses can do things that defy their conformation or way of going. The Canadian grand prix dressage horse (PMU baby?) -- I forget his name -- is about as downhill as any horse I've seen, but there he is piaffing away.
My .02. Maybe someone out there who knows for sure will respond...
I agree that looking at just where the front feet are going can be misleading. I once heard a trainer say, while watching an upper level horse doing a test at a show - "What's that Grand Prix front end doing on that on Training Level rear end?" The front feet mean nothing without the engagement and collection of the hind legs! But I do think that DAP is fun to look at and useful for evaluating young unbroke horses.
ReplyDeleteFascinating - I love learning more about equine movement.
ReplyDeleteI think you're right about not getting obsessed over this with one's own horses, but it's a valuable tool when looking at the bigger picture.