The critical power model for intermittent exercise

This paper develops and illustrates the critical power model for intermittent work. Model theoretic development reveals that total endurance time is always a step function of one or more of the four independent variables: work interval power output ( P(w)), rest interval power output ( P(r)), work interval duration ( t(w)), and rest interval duration ( t(r)). Six endurance-trained male athletes recorded their best performances during the season in 3-, 5-, and 10-km races, and performed three different intermittent running tests to exhaustion in random order, recording their total endurance times. These data were used to illustrate the model and compare anaerobic distance capacities (alpha) and critical velocities (beta) estimated from each type of exercise. Good fits of the model to data were obtained in all cases: 0.954< R(2)<0.999. Critical velocity was found to be significantly less when estimated using an intermittent versus continuous running protocol.