How would you use fast and slow twitch muscle fibres in a 1500m race?

Most runners don't think of themselves as muscle-bound.

That's a term reserved for football players, weight lifters, or Charles Atlas when he kicks sand in the face of a skinny runner on the beach.

But the reality is that the human body has more than 600 muscles. We runners use most of them. And training sessions designed to recruit and strengthen our running muscles are the key to achieving top fitness.