Power relies strongly on phosphagen energy networks, which uses ATP and creatine for energy. This is depleted quite quickly, therefore, it also relies on glycogenic networks, which uses stored glycogen for energy. Power exercises often have powerful and rapid movements. And plyometric/ballistic contractions are also used. Plyometrics are stretch-shortening cycles that attempts to maximize spring potential of the muscle tissues, through fast reflex actions and resisted jumps.