Sigh... It seems that more and more, on almost every single COH thread I go to, sarcasm and criticism drown the original post. I opened this one to look at a beautiful photo of a lovely and horse and rider. I should have stopped right there rather than read the comments. It is depressing and disturbing.
I gave my explanation with this link: http://www.ridingart.com/toe-flip.htm It's clear to me, and if you or others don't buy into it, that's ok. Of course you will find countless videos showing the hind hoof flip, just as you will find them showing all kinds of faults. That's how dressage is; perfection is near unobtainable. It's a super photo of a super rider and a super horse.
An informed person would have to question the information provided by that link, and why the author feels qualified to make such claims. I guess if you like riding horses with mincing gaits, then it's just fine.
The pix has not only airtime/is uphill/but full reach of the shoulders. And there will be about 8" of over stride (was there in person as well!). The horse has gotten a smidge low (curb effect) and is a smidge pushing (hence hind ankles start to torque). The forefeet will land where they are pointed (unlike the nano second pix). When the hindfeet show themselves to the sky with unequal stride length fore and aft there will be no o.s., the horse is only pushing the load (nanosecond pix).
And imho Keen's body type goes much more to the dam side of the top line, not the stallion part of the top line. (But the stallion side of the dam line comes through as well.)
Keen yes. The nano pix because of the lack of even stride length fore and aft, no. The fore legs should reach and land where they point (not drop down, or worse yet be pulled back in landing). The carriage of the top line (too high/low/compressed/long/responding to curb) WILL all affect that. As riders we must understand how what we do/inspire/allow affects the stride in front and behind. We need to inspire enough collection to create thrust/reach, enough room for the hindlegs to step through (rather than wide which is shown in some of the vid), proper carriage to have the forelegs reach, and lengthening of frame/overstride.