A Proposed Fracture Resistance Formula

The formula is ready to be rolled out.
What's being calculated is minimums in terms of what's necessary to achieve and maintain fracture resistance (FR). The variables are distance, speed and frequency. Here it is:

4F in 12/5 sec./f every 7 days = FR

What does this mean--how to interpret?
First--each variable is expressed in terms of its' own minimum. If the horse in its speed work travels less distance than 4f the work will be without a training effect in terms of injury prevention/fracture resistance. If the speed is slower than 12.5 sec.f same deal--it's absent FR training effect. More than every 7 days, ditto.
The import is that all three minimums have to be met or else the particular work will be without an FR training effect. Consider each variable in the stated formula the RR blog absolute minimum!
Of course, even before the formula appears the comments come in with questions. Anonymous chimes what about 8f or doing 6f in :13s. Bill Pressey comments that he's favoring 2 speed works/week, one faster at 2-4f in :12S/one slower 6-8F in :13s-:15s. Sounds nice, but beware. I have tried it on track. Lot's of problems that I will save to detail when/and if, I ever get to performance. My own thought process in terms of an ideal performance/injury prevention training schematic has been, for a while now, somewhat similar to Presseys but 2 speed works every 5 days, one short and fast, the other long and slow. Note though--I'm not there yet. Fraught with numerous practical difficulties when you get the horse on the track!
There obviously are many ways to peel the apple for injury avoidance and performance both with our horses and in athletics in general. There are so many variables we can tweak! #1 though, before we start playing around, is to know what the heck we're doing in terms of preventing injuries to our horse because, unless we know that, nothing else will matter for that particular horse.
Thus, a closer look at the above formula, tweaking it, or even--does it have any validity at all--is next.
Training: The horses hardly seemed all that happy this morning with the plunging temps. Unknown how these little birdies keep from freezing solid. If they dislike the cold, heck with 'em. Let 'em fly south. The knee bump is reduced a bit. We're still off in anticipation of spring starting this weekend.