CRITICAL POWER

FROM CYCLYNGPOWERLAB

This calculator uses a simple statistical technique (OLS regression) applied to power variables in the manner of Monod & Scherrer's "Critical Power" model to estimate the time dependency of a riders “mean maximal” power output from the riders Anaerobic Work Capacity (AWC) and Critical Power (CP) which are computed from "best" tested power values at 2 or 3 durations. Mean Maximal Power means “the highest average power the rider can maintain for a specified duration".

Applications of a Critical Power Curve

• Estimate a riders sustainable power output at any duration, particularly useful in developing interval training that will be well matched to a riders ability, given a small number of power field tests.

• Estimate the effect of changes or improvements in one duration specific sustainable power on other durations.

• Calculate “Functional Threshold Power” (60 minute Mean Maximal Power) from less arduous field tests of shorter durations.

• Establish training zones from Functional Threshold Power.
  
  

Inputs

• The only required inputs are field tested observations of sustainable power at 2 or 3 of the selectable durations. You can input values in the "Tested" column only, or additionally input values in the "Scenario" column to study the effect of changes in tested power values.

• Rider weight in Kilos is required to also express Wattage outputs as wattages per kilo.

• Tested / Scenario. When applicable you can select between displaying numbers based on the "Tested" or "Scenario" power inputs.
  
  

Outputs

• CP. Critical Power in Watts. If a rider had 0 Anaerobic Work Capacity his Critical Power curve would flat-line on this number.

• AWC. Anaerobic Work Capacity in joules.

• R^2. "R Squared" measures the "goodness of fit" of the model. Think of this number as a percentage, where 1 = 100% and would indicate the model could perfectly account for the riders sustainable power at any duration.

• Predicted Power for Duration. The riders Mean Maximal Power predictions at a popular range of durations upto 60 minutes.

• The chart displays tested power values and the coresponding curve of predicted critical power. When applicable it also shows scenario values and the scenrio critical power curve in a lighter colouring.
  
  

Power Training Zones

These outputs specify the bounds of popular "zones" of training intensity in watts. These values are based on the riders "Functional Threshold Power" which is the 60 minute power prediction.

It Works! An applied example of Monod Critical Power...