Theories

Theory 1: equine speed work presses on bone fibrils, reducing spacing between them, and possibly causing fibrils to adhere together.

Theory 2: adherence would be caused by 1. the crystal calcium blobs joined together(were the image clearer, this is highly organized material)and 2. bone glue proteins located in nano spaces between fibrils.

Theory 3: Theories 1 and 2 are incorrect. During equine speed work there is an accordion effect on fibrils whereby with each stride fibrils come together and then separate again as hoof leaves ground and becomes air born.

Theory 4: there is no spacing between racing equine TB fibrils since pre-race speed work has already eliminated (over time) any inter-fibril nano spacing that may have existed in the unexercised horse. In this sense the fibrils have already optimized in terms of density by the time we get to the race.

Weighty questions!

The below representation from Hansma meant to demonstrate bone glue sacrificial bonds during fracture also shows inter fibril nano spaces(unfractured fibrils at the left). These were measured by Planck as 2nm. The image e.g. is probably about 500 nm.

To consider the 4 theories we need also consider the organization of fibrils and fibril arrays into the larger structures called osteons. Note below on the above right "collagen fiber orientation":

The above image shows the manner and position of fibrils in the osteon. Visualizing this organization during speed work, is it a reasonable supposition that pressure on the osteonal structures would extend to individual fibrils and fibril arrays? The same process would work on the non-osteonal cortical bone outside the fibrils that extend to the bone's surface (the shins!).

If indeed speed work would press the fibrils together, how might this effect post-race damage, remodeling, strength, etc.?

Training:

Mon. 4/11: Off.

Tues. 4/12: Dry all week. Unable to believe it! w/o aborted after 15 min intermittent riderless bursts on craggy ground due to sprung shoe. Lucky for once, as horse this date is scheduled for shoeing, as opposed to a" newly applied" sprung shoe that would have ticked me off severely!