Post Breeze/Race Remodeling

The "newest" (equine bone) studies by Robin Peterson DVM turned out merely to be further discussion the Maryland Shin Study.

There seems to be little new that I am able to find, but the nice Doc Peterson summary of Nunamaker presents some interesting points even if Nunamaker's whys and wherefores are growing a few whiskers in light of recent human research.

Nunamaker's concludes that fracture resistance (FR) depends on exercise load, and, interestingly, that a small increase in bone quality, size, density, etc. provides a geometric addition in strength. Dr. N notes: Appropriate speed exercise "stimulates" bone remodeling that is "quick" and "immediate" (as opposed to slow and long term), and the initial process (at least on the surface of the cannon bone along the angle of strain) involves the laying down of weak "fiber bone" (as Dr. N. terms it) under the periosteum that may be damaged in the form of bucked shins by a questionably conceived program.

I'd probably reword part of this summary from Doc Peterson by noting the remodeling processes (instead of remodeling) are engaged quickly and immediately. A fine distinction, but necessary to understand that surely Dr. N. was not claiming that fiber bone was laid down under the periosteum by the next breeze 3 or 4 days hence!.

Thus, it is the remodeling processes that we are interested in post race, and how they will work with passing time. And please note that for my example we are in fact dealing with an appropriately trained horse up to the speed event, and that the speed event was carried out appropriately to in fact engage these remodeling processes, which means that it had to last 4f and go in :12.5s for race appropriate FR.

I am continuing to think this through in a busy personal schedule. To date, I've come up with this as #1.

Post race as in humans at some point, however long it takes, osteo blast/clast remodeling will commence along the angle of strain just as Dr. N speculated. But, in horses, probably, there is a lot more happening post race in addition to osteo blast clast remodeling, and possibly these additional processes indeed occur quickly as Dr. N thought.

If the mineral lattices macro and micro compact and gird themselves against impending force during the breeze, post breeze they will rebound probably back to their original size. However, there is other material within the bone that also during the breeze suffers compaction.

Let's begin with the more malleable bone glue proteins that encase each cell, and consider what occurs when this substance that possibly has the consistency of very dense Vaseline compacts during the breeze. The nature of the such material is such that we may believe it will fail to rebound back to it's original volume. This has two important consequences: 1. the material will be more densley pressed against the lattice and presumably remain that way (although Hansma notes that the sacrifical bonds that tighten and shorten in response to applied force will lengthen again and relax on release of the force.) and 2. This squeezing and compacting of material will leave some micro or nano spacing behind, a vaccum if you please, TO BE FILLED IN BY NEW AND ADDITIONAL BONE GLUE YET TO BE LAID DOWN.

This two fold process, I am thinking, that leaves existing bone glue pressed more firmly against the lattice and new glue laid down into the spacing left behind will within a reasonably short period provide a slightly heavier bone more densely and solidly packed with bone glue. How quick, next post.


Training:
Wed. 3/18 Rod is off after his first official speed work yesterday.
Art: when will we get this horse's first breeze? The horse himself decides the question. This day with a cotton bandage protecting the frog Art is taken out for a 15 min trot-gallop as we continue to get his sea legs back, but Art takes off on his own and we get one nice 1.5f gallop in close to :13s with a nice lead change in the middle. Mark it down as Art's first official breeze.
Thurs. 3/19: Going fast every single night results in some rider fatigue so we decide on an easy riderless workout with breezing tomorrow. The best laid plans go awry again as Rod is really into it this night, and we decide to go with the flow: Riderless 4 x 2f all out. Will gallop slow tomorrow and have 2nd breezes Sat.