Carbohydrate is stored locally in muscle cells as glycogen, the primary fuel source for initial exercise demands.

“Carbohydrate, on the other hand, is going to be stored locally in the exercising muscle cell, and specifically in the cytoplasm. - As glycogen. - As glycogen in the store there. So what's going to happen initially, your initial demands for exercise, or for fuel, are going to come from the glycogen stored within the muscle fiber itself.”