Not sure there is direct proof, but simptoms are there
it could be speeded up by things like genocides, wars, purges of the inquisition and so on
Also maybe this is a myth, but I read like that in an ancient treatise that a charioteer was chasing a running horse. This speed is 2 times greater than the speed of a sprinter, that is, none of the modern men achieves this even approximately.
Here is still circumstantial evidence. In the world of animals sexual dimorphism in tertiary characteristics is obviously higher. For example, composition of musculs of bulls differs from cows greater then men's from women's. Bull have more speed musculs