Although we all possess the capability for anaerobic and aerobic energy metabolism, the capacity for each form of energy transfer varies considerably among individuals. Sports such as football or weightlifting, rely almost exclusively on energy derived from the muscles's pool of high-energy phosphates. Researchers have proposed different tests to estimate the power-generating capacity of high energy phosphates: stair-sprinting power tests, jumping-power tests or sprint cycling. In reality, however, it is difficult to obtain precise physiological or biochemical data during all-out exercise of brief duration.