The video of the pony, is well collected, correct? But the beginning of the take-off still needs work, but is impressive. You did say very correct but both hindlegs should kick out together and be equal in the kick out, or am I wrong about that?
The sidesaddle lady is very well balanced, but not in a true collection, right? She's very fluid and she's very easy to watch.
You've certainly brewed up a small storm here, April.
Did you know that currently, and for that matter, as long as I can remember, when a Western horse (style) is said to be "collected," it can and usually does mean that he is moving low and slow in relation to the ground?
Just thought I'd add to the mix.
I'm inspired to move toward the explanation that is more involved with how a horse's physical attitude around his center of mass. The 'balance,' issue.
What is the the body doing around and relation to the center of mass?
One could say, I suppose, that if a horse is not balanced then he is falling down or in a state of falling and catching himself, if he, and the rider, are lucky.
So if balance is being maintained would we assume he is collected? Nope. Obviously.
An extended horse is really falling down if his balance is being maintained.
Or, conversely, could it be that we, and in fact all moving living creatures are in fact falling down and just catching ourself most of the time?
If this view is considered, then the dynamic changes. We would then assume that unless we are standing still we are in a state of constant recovery from falling.
Is your head swimming as mine is?
Working back from the point of very nearly falling and only catching one's self at the last instant could be, I think, (and guess) what extension is about.
And as the horse gradually retracts about it's center of mass, it is in fact becoming "smaller" from front to rear, thus have a more compact package to balance.
And of course we know if we've ever carried heavy things, that bulk is a huge factor in our muscle and ligament, and balance recovery. The same weight item in a small compact space say a box of books tightly packed, is far easier to control (emphasis on control) than the same weight spread out over a larger area of the 'cube.'
So when we compact our horses, that is shorten their length, we are seeking a condition where the horse has both and easier time bearing the load, and more control over the position of the load ... his and our body.
Now this flies in the face of some older theories about the horses capacity to bear weight, and certainly makes me pause to consider some of my own viewpoints on the matter.
Could it be that collection, done in some manner that we as yet struggle to discover, is easier on the horse than extension?
How much is just right for the entire package of horse and rider (or horse alone)?
My feeling about it...and I mean literally how I feel and have felt the horse moving beneath me bearing my weight and his, is that there is such and optimal, or optimum point.
The compression of the neck toward the shoulders, bringing the head with it of course, the degree of angle in flexion at the poll that changes the head center of mass (weight) relationship even more as the nose reaches the perpendicular plane of the face, the tilt of the horse's pelvis not just to engage the muscles and tendons in a new more powerful way, but the pelvis, hindlegs, etc, being repositioned closer to the center of mass of horse and rider, all bear on the question of collection and just what it is.
I like that you have managed to bear down on this and not let it go.
It needs the kind of examination rigor that the scientist with her microscope and other analytical tools can bring to bear on a sample.
You seem to be making the focus clearer just by pressing on, as every is that's now involved with it.
I think the challenges you opened with are the same ones felt by the various experts cited. How DOES one define something that is not static, but in fact continually a dynamic as this is?
Can collection then be defined not as a fixed attitude, but instead a range of attitude of horse around his mass?
It might mean that to say a horse is collecting, and thus collected to a degree, begins at whatever point of extension the horse begins to move to a shorter length, and start the other events that make that happen, even if in a still photo he appears to be extended.
Simply more collected than he was a moment before because of the direction of change of body attitude.
It may seem I'm beating this into a pulp but in fact I've mulled these very things for a great many years, and never really felt resolution.
I'm not sure I, or anyone else ever will completely resolve this.
Take just one item, say circulation ... blood flow. Suppose we could examine how that changes during a phase of collection and how it might effect a muscle group (as blood flow most certainly would) in it's speed and intensity of tension increase?
We focus on building flexibility and muscle capacity for power and surely blood flow would be a factor.
If it's slowed, for some reason, (I'm thinking of Rolkur) or de-oxygenated by lung restriction by blocking airflow, what happens to the capacity to collect?
Is it any wonder in standard current dressage rides we see the horse lose those attitudes we know and value as being true collection?
The back caves in, the rear legs begin to trail behind, the forehand becomes a prop rather than a power stroke for the horse, the stomach drops.
Yet, weirdly enough, and even more confounding, the length of the horse stays nearly the same as when we recognized them to be in collection ... yet he is not.
Could my eyes have been deceiving me?
And coming full circle back to the "collected" western horse: he has not shortened his length and gathered closer in to his center of mass, has he?
Head down and neck extended, hooves almost sliding along, hind legs trailing behind.
I think I'm more confused than ever. But I do have more information to consider and determine, if I can, what I wish to consider collection.
But then, I think that AND has something closer to the ideal in defining collection than any other source I know of.
I just can't tell exactly what that is.
It's sort of like describing an eel. I can tell you that it wiggles, it's kind of longer than wide, but darned if I can give you an idea of it's exactly outline.
It keeps changing right in the middle of definition.