Big Brown and Mineralized Collagen

Steroids right now cast a pall on everything for me. But, that was kind of a neat race in the Haskell today, even if I suspect that Big Brown was running against chemical Zito. But, a neat race that I played over and over. They avoided giving it to BB with that 1:35.1 mile. My impressions: BB's gained a lot of weight since those facile early season runaways. And, he's running clean and less dominant. You also might question a horse running 1 1/8 mile on 5/8 works. Will be interesting how Dutrow plays it from here on in. Me, the horse would be back on track (if he's ok after that drifting out), on Tuesday aiming for the Travers.

Back to bone cells. A couple pictured here--unidentified at left, a collagen fibril above right. You could simplify all this and say that in the weight bearing phase of the stride bone material is
squeezed or pressured. "Bone material" covers a lot of territory though, and we need to know what we're specifically talking about. Three main ingredients to our cannon bone:


1. collagen
2. mineralized lattice
3. sticky gunky proteins called bone glue.

I am imagining that bone in the fetus begins as collagen and commences mineralization. By the time of the outset of training you'd think there is a significant mineral lattice already in place, and that in the course of training the bone osteoblasts are laying down additional collagen surrounded by bone glue which gradually mineralize as we go. I was unable to find anything about how quick the mineralization process is, but, I think we can surmise that it's slow instead of fast. For a single collagen fibril to mineralize from creation to the time it's solidly encased and itself begins to mineralize, I'm thinking this process has to take at least two months, and probably more. I get that when I think how fast a broken bone mends. Broken bones take months before they're as good as new and I suspect this is because of the slow process of the mineralization.

So, what we have there at the outset of training is spongy bone at the interior near the blood vessels and on the condylar aspects, with a significant mature minerlized layer going out to the exterior of the bone and finally the ostoid consisting of recently layed down, unmineralized collagen.

What changes during training? We know from the photos that the mineralized portion of the bone grows thicker both inward and outward. Why this happens in response to exercise also gives a giant clue on what's happening with our bone material during the breeze itself, next post.

Training:
Sat. 8/2: I developed the intuition this night that the horses should lay off. I'm heading out now for Sun. and will do some tack work and then some short riderless spurts.