The force membrane collects 500 frames/second, so yes, it does pick up information about secondary impacts.

The trouble with blaming a crack on imbalance is likely to be deciding which definition of balance to use as your standard.

oh gawd! not again!

The picture above shows the loading patterns for a horse with a crack at the coronot on the medial side of the hoof. This horse was sound at the walk, and the area caudal to the crack was stabile on physical examination.
The medial heel was bearing very little weight relative to the lateral heel. This horse landed flat, loaded centrally, and the breakover was in the middle of the toe.
The graph shoes about 10 strides. The red line shoes the force on the LATERAL heel quadrant, while the green line shows the force on the MEDIAL heel quadrant.
I was very surprised by these readings. It is possible that the horse was altering his landing pattern based upon proprieception (or pain), but the horse was relaxed and moving comfortably during the test.
Mike is obviously correct in pointing out that vertical pressures are measured here, and there are certainly other forces at play (shearing forces, for example). I would observe that floating the heels is apparantly not necessary on the horse, as that is already being accomplished in spite of the flat shoe in contact with the hoof.

reillyshoe wrote:
Pat, did you mix up red and green? Isn't the red showing greater force...but you said red is medial heel?

One condition that I think alludes us and is seldom thought of is laminitis. Consider the amount of distortion stress that can occur in the hoof due to even mild laminitis. Also consider the causes of inflammation of the lamina. It is logical to think then that a medial/lateral imbalance can occur just from displacement of P3. So Pat's statement is correct when he says other things may be occurring other than an out of balance trim.

Phil Armitage wrote:
Who knows. I can talk about what I've seen but wuthout measurements, large numbers of samples and so many variables, it's hard to draw conclusions.

I suspect that part of the sheared heel thing, which often goes along with quarter cracks, is hereditary. I say that because I see generations of horses and multiple horses, otherwise of shared blood lines, with almost identical feet. They may have different owners, trainers and farriers but the same feet with the same problems.

I've seen way too much of it to buy into writing it off simply as M/L balance or being "farrier-made".

Mike Ferrara wrote:
yup, more force on the lateral heel.

Mike Ferrara wrote:Actually, he said: "The red line shoes the force on the LATERAL heel quadrant, while the green line shows the force on the MEDIAL heel quadrant. "

Rick Burten wrote:
Come on, he's the only guy around with all that fancy equipment and might eventually answer some of these questions...don't pizz him off:D

I edited my original post after Mike pointed out my error, no offense taken here.

reillyshoe wrote:
I didn't figure there was. I was just razzin Rick.