The pump... It is the holy grail of bodybuilding. It is that most addictive of sensations that keeps gym rats hooked for life. It is euphoric and invigorating, an intense swelling of the muscle caused by a training-induced cascade of blood… It is a rebirth experienced on each worthwhile trip to the gym. The pump is instant gratification… An automatic reward for all of the blood, sweat and tears you spill on the gym floor. The pump is instantaneous growth… It is the immediate invigoration of dormant muscle fibers.