Since its introduction by Monod and Sherrer the Critical Power model has been applied to the analysis of cycling performances, Weff (the anaerobic capacity) is considered to be a constant quantity. However examination of the relationship between the capacity that can be generated from Weff at any given power, described adequately a non-constant quantity for Weff.
Relation between Weff and Power
Note that the y axis is expressed in Joules or capacity, and the x axis has become Watts or power. The plotted line is the capacity that can be generated from Weff at any given power.
Relation between Weff and time
Note that the y axis is expressed in Joules or capacity, and the x axis has become sustainable time. The plotted line is the capacity that can be generated from Weff at any given time to exhaustion.
This cyclist has access to his full Weff of 148 kJ for all intensities up to his supercritical power SCP = 444 W. For higher intensities Weff drops dramatically and reduces eventually to 0 at Pmax = 1405 W. For any sustainable time t < Tscp and intensity > SCP the available Weff is much lower than the saturation value. This indicates that for this cyclist any test at sustainable times shorter than Tscp = 20,4 minutes will inevitably lead to anomalously high values of CP and low values of W’.