Because if the energy charge value is high, that means ATP to amp ratio will be high. So what happens is these excess ATP molecules move on and bind onto the regulatory side of phosphor fructokinase and what they do is they essentially decrease the affinity of phosphorinas for the substrate molecule the fructose six phosphate. And so what happens is step three basically stops taking place. And if step three stops taking place then we're not going to produce the ATP molecules and that makes sense because if we're not exercising if we have rest we don't want to produce ATP molecules and so that turns off the process of glycolysis. But what happens if the energy charge value is low? So in the case of us exercising what happens is the ratio of ATP to Amp decreases and what that means is we want to produce those ATP molecules because we want to be able to contract our muscles quickly and effectively.