Osteons And Exercise

Focus first on the osteons within the larger bone context. Osteons are the next basic structures up from the microscopic forming the length and breadth of the bone material. The Wikepedia rendition is found here:

http://en.wikipedia.org/wiki/Osteon

The osteons are several millimeters long, .02 millimeter in diameter, contain patterned collagen in various states of mineralization with a "plasticity" involving the ongoing constructive/deconstructive processes (osteoblasts/clasts) that suggests changes in response to stress.

Consider first their size--"several millimeters would be short instead of long within the cannon bone. The thickness, a near microscopic .02 millimeter, suggests numerous strands with the cylindrical tubes connected by a weaker interosteonal collagen. How does our exercise protocol affect these structures?

Possible questions:

1. increases the size of the osteons, OR
2. increases the number of osteons, OR
3. both.

As you may imagine, human orthopaedics is very little concerned with these questions. The insufficient stress of human activities would never bring these factors into play. Different story, of course, for our equines, where number and size of osteons MIGHT be a factor to consider in achieving fracture resistance (FR).

Needless to say we are without any research information, though there has been some speculation of the equine sort.

Tom Ivers comes to mind where in Phase I (slow gallop phase) Ivers advocated lengthy slow gallops up to 6 miles per day at a 3:00-3:30/mile rate of speed. Ivers called these lengthy gallops "money in the bank" in terms of gradual build up in tissue strength.

But, where did Ivers get this notion that increases in workload might result in increases in tissue strength? I read and listened to most of what Ivers published, and am unable to recall any analysis of cause and effect within the bone or collagenous tissues. Were these notions of Ivers merely intuitive?

My conclusion, after due consideration, would be--yes and no. Certainly the concept of tissue adaptation in response to stress or training is obvious to anyone that's been in a gym. Yet, this begs the question. Do we really get stronger tissue or bone materials from--say--galloping six miles a day or going on with Phase II and III of the Ivers program? Based solely on the work of Tom Ivers, we don't really know.

Huh? you say. But consider--is it conceivable that Ivers' six mile gallops, instead of increasing the strength of tissue for sprint racing, instead caused collagen to be laid in a different and very possibly weaker pattern than would sprint work? There is, after all, quite a different effect between the flicking of slower galloping and the pounding that results from furlongs in :12s. What I will post here after will indicate that the answer to this question may well be in the affirmative.

The moral of the story is that when we're talking about injury to our animals, catastrophic breakdowns and the like, it would be enormously helpful if we get beyond the sort of intuitiveness in Ivers, even if it is informed intuition, and ellicit precisely what is going on. At present this amounts mostly to speculation, which will continue next post.

Training:
Thurs. 7/30: Ground conditions force choice between slow trot gallop or riderless speed work. We opt for riderless speed in a light w/o so we may continue with light galloping next day. 4 x 2f full speed in mud as horses get surprising traction. About 3 miles total volume.
Fri. 7/31: Finally dry. 1.6 miles of trot- gallop for each, with a strong finish.
Sat. 8/1: One day of dry followed by another inch of rain. Off