Horse Performance Edition I

You can have the best trainer in the world and a crap horse and it will not change your horses genetic structure. But I am asking these questions to the performance horse people around here, maybe they can teach others a bit.

So we will start at the ground work of their performance, what really makes them tick, less all of the psychological side (training.)

In regards to horses:

How can a muscle become striated?

Why does a muscle contract?

What combination, mixtures create (fuel) muscle contraction?

What are the inner workings of a muscle cell and what can I manipulate for performace?