The Nitty Gritty: Bone Cells During The Breeze

Probably my boys would like to avoid racing against Go Country Grip, but for the present I'm more interested in what happens when the lead leg of that speed ball smacks into the ground. When you're on board you hear the smack followed shortly thereafter by the jarring and vibration as the weight of the horse shifts on the follow through. You can pick this up visually with some effort at slow mo.

In terms of what occurs there's a lot to consider. If you look at a leg bone attention is first drawn to the macro level, the bending, contortion and expansion and contraction of the whole bone. But, absent overbearing torsional force perhaps in the form of the bad step, the bone as a whole generally holds together.

At the micro level we consider the various part of the leg bone as illustrated below:

I believe we're primarily concerned with areas:
1. The cancellous spongy bone that we'll find near the blood vessels in the interior portion.
2. The cortical or hardened bone as we go outward which is the maturing mineralized matrix.
3. The thin outer layer of unmineralized collagen beneath the periosteal membrane..

And, of course, there's this primary area of concern:
which would be the condylar or end aspects of the bone which for our youngsters contain the still developing ephysial plates as well as developing spongy bone. Here's another view:

Considering the force that applies to the bone as microscopic structure and what we know about how they hold together, which includes:

1. the manner of the layering of the cells.
2. the mineralized connections.
3. the proteins which make up the bone glue and their bonds which also include the sacrificial bonds which lengthen with pressure and come back together with the release of pressure

possibly we can conjure what occurs to single bone cells while the horse is running. You get, if you think about it, is a single bone cell that's undergoing momentary intense pressure and contraction, and then release, repeated 230 times over the mile .

Next post I'll look at what's happening in a single bone cell in the areas of concern.

Training:
Thurs. 7/31 still a total mess from the 2.1 inches of rain 2 days ago, but, the paddock is just dry enough for riderless work. 10 min of slow trot-gallop then the two year old was removed. Art then did 2 x 4f as fast as conditions allowed, probably 14-15 sec/f, it was a good workout considering the horse was motoring through the mud. We skipped tack work due to conditions.
Fri. 8/1 still quite wet, the horses did 2.5 miles of trot-slow gallop without stopping. Then 10 min. of walk under tack for each horse.