Whenever Grok needed to lift something really, really heavy, he drew upon the adenosine triphosphate phospho-creatine (ATP-PC) energy system. If he saw an opportunity to cut off a fleeing buck and had mere seconds to act, Grok would engage his ATP-PC energy to summon the requisite sprinting speed. Today, we use the very same energy pathways. The very same potential for feats of immense, instantaneous strength and power resides in our muscles (some of us more than others, sure, but that can be altered through training). Of course, the ATP-PC energy system is just one of three primary pathways in our bodies. All three utilize adenosine triphosphate (ATP) as the primary energy source, but the speed, intensity, and duration of our muscle contractions determine exactly how that ATP energy is tapped, released and recycled.