Pakewi,
I agree that any method which was able to produce consistent results did so because it was able to produce a positive (toward the result) adaptive response (not sure why you are writing about external, maybe you wanted to say phenotypic).
With a bit of reductionism, we can say that those methods were able to increase (and optimize) the force production relative to sprinting.
But one question is how,and another question is why.
You are not Jay Schroeder, who lacks the Italian charm.