Appropriate Remodelling

Per my immediate prior posts, my thinking: you start to get serious remodeling effects after the horse is down the track 60-80 strides at :12.5/f, and at that point the effect increases dramatically and continues on a steep increase to about 6.5-7f at which time the "increase in effect" commences to level off rapidly. Needless to say, the total effect depends on the condition of the horse to begin with, but, all other things being equal I'm guessing that's about the way it goes.

Last post I listed the processes that are occurring, and now, our horse having finished it's work, what happens?

The first thing we generally notice post work or post race is cannon bone heat. Depending on the prior bone fitness of the animal post race cannon bone heat varies from severe to mild. For extremely conditioned horses cannon bone heat will almost completely dissipate within a couple of hours for the reason that at least some of the heat you're feeling is merely overall system heat instead of heat emanating directly from the bones. System heat, or the horse's enormous body heating up from the effort goes away quickly as the horse cools down. It's the bone heat that's left over after the cool down that concerns us.

A fit horse will still exhibit some mild cannon bone heat 12 hours post race which the unfit animal might continue to exhibit heat for several days. My own personal gage has been if I'm getting cannon bone heat (open hand directly on the cannon bone with heat radiating into the hand) 24 hours post race, even mild heat, this is a concern. Heat 48 hours post race indicates to me a problem, and that there was some severe bone degradation during the race for which we now need to compensate in our exercise protocol.

Of course the heat partly results from the remodelling effects listed last post and is actually the beginning of the remodelling process. Cannon bone heat that continues for any length of time is actually a low grade inflammatory process that will speed the healing. Those that understand basic chemistry know that with increased temperature we get faster activity at the cellular level.

What happens precisely in the post race/post work remodelling process? Here are my thoughts:
1. Bone vascularization increases, builds, and grows in response to exercise similar to what occurs in muscles but probably at a snails pace comparatively. I suspect that one of the things we want to happen is the branching out of new capillaries within the bone tissue, which presumably would be part of increasing density and growth.
2. Increased enervation. Same deal.
3. Repair and growth of the bone surface at the cellular level. Again, just a wild guess on my part, but, I am supposing that the horse in early training has primarily living collagen on the bone surfaces which grow in thickness and density in response to exercise, but that at some point in the bone growth you get deposited of necessity increasing amounts of non-living mineralized tissue which at a certain point, because it is non-living will quit growing. This process (if I'm guessing correctly) would prevent the bone from increasing in size and thickness beyond a certain point where there is insufficient live collagen on the bone surface for continued increases in diameter.
4. Interior bone: filling in of the matrix/lattice work as well as increasing the size of the lattice. How does this happen. I know from my reading that the osteoblasts and osteoclast cells do the resorption of damaged tissue and rebuilding on the bone surface. Unknown whether you have those cells working on the interior of the bone. But, I have read some articles involving the "shaking" process that occurs during exercise, and you'd suppose that in the shaking some minerals are repositioned after being shaken out of their moorings. The original vacant spot will be filled up by new calcium/mineral deposit, leaving an overall net increase in deposits both living and non-living.
5. Bone glue response: does the sticky living collagen bone glue described (and photos) in my warm up posts in July increase in thickness and quantity. I'd suppose so as part of the cell reproduction process. More deposited minerals need more glue.
6. Damage repair: You can Google damage repair in bones, but what's being referred to is those parts of bones were microscopic fissures occur, both surface and interior that have to be filled in. If there's a fissure, fairly soon after exercise fluid will fill it up to commence the repair process. You may imagine the scenario of an unfit animal being raced, a lot of fissures being caused, and the beginnings of a stress fracture resulting as the horse is taken back to the track too soon.

The above processes if handled correctly, presumably result in stronger bone with the crucial, desperate question for our horses, how long's it take, next post.

Training: One more blast from the north yesterday. With every one we think it'll be the last, then comes the next one. 6 degrees this morning with 1/2 inch of snow. But, my horses had their normal off day yesterday, and we'll train this afternoon in better weather.