And let's imagine that we're essentially sprinting. So as we begin to sprint initially what happens in our skeleton muscle cells? So in that skeleton muscle cell, we need to basically produce the ATP for the active mice and fibers to actually contract. And so the glycogen storages are essentially depleted. We break down glycogen into glucose six phosphate and that is then used to produce pyruvate molecules and ATP molecules and then to reform the NAD pluses. Because initially, as we begin sprinting, we have plenty of oxygen, the Pyruvate will go into the mitochondria where we produce many more ATP molecules and regenerate those NAD plus coenzymes that are then reused by glycolysis.