That means we only use glycolysis to form our ATP and we also use creatine phosphate. So these have a large diameter. That means they produce the greatest contractile for us out of all these three muscles. And these basically fatigue very quickly. So that means when we're sprinting and that requires let's say, 10 seconds, these are the muscles that we're going to use. So because we don't have too many capillaries, we don't have too much oxygen.