[billmckinneygolf]

I think we can get an adaptation response by training for it.
That is, the fibers can actually change from one type to another. Parapelegics' muscles turn to pure fast twitch as a last ditch survival effort.
There's more to this..Human Growth Hormone, Testosterone and other hormones our bodies and brains create.
See www.arthurdevany.com for a good explanation of this stuff. He talks about how we've evolved and should be expressing much more fast twitch muscle.