Critical Power: An Important Fatigue Threshold in Exercise Physiology Synopsis

Critical power is the maximum level of exertion an individual can sustain for an extended period of time. In the concept of critical power, each individual has a fixed amount of energy they can exert above critical power before they reach full exhaustion. This can be expended in high exertion, short-duration exercises such as sprinting or lower exertion (e.g just above critical power), longer-duration exercises such as mid-range running. Critical power is closely related to a person’s VO2 Max or the maximum rate of oxygen consumption. There is a fixed amount of energy an individual can exert above critical power before full exhaustion. The reason for this is because, during exercise above critical power, the body consumes its limited supply of high-energy phosphate stores and produces lactic acid which causes the feeling of fatigue.