A new paper continues to add to the body of scientific work showing that Critical Power (CP) and Functional Threshold Power (FTP) are not interchangeable (though they are correlated closely).
Note some quality names in the authorship, such as Dr. Bettina Karsten (who has written several papers on CP) and Dr. Nathan Townsend.
Bottomline : CP and FTP are co-related but do not mean the same thing. Plus, wide limits of agreement among individuals. As the paper states : “Caution should consequently be exercised when choosing between FTP and CP for the purposes of performance analysis.” This cautionary note was seen in some past papers as well, with the same observations on wide LoA.
Let’s fall back to science and recognize each of the above terms for what they are worth. There is value in understanding that CP and CP alone is the “maximum” metabolic steady state, while FTP is a submaximal lactate steady state.
Couple of thoughts to go along :
Under the tab “Power”, the footnote under the power curve states : “Estimated FTP is calculated using power curves from FastFitness.Tips and Morton’s 3 parameter critical power model.” In light of this post, I’m not sure if “FTP” and “CP” should really be put in the same statement as if pretending they are pointing to the same thing. To continue to provide value for users who use CP and those who use FTP, there could be separate eFTP and eCP estimates laid out on the curve. Apologies if this is already provided but I couldn’t locate it.
Several (simpler) models for CP estimation would be welcome. Morton model may not be perfect in every situation.
Is FastFitness.Tips an original source of the body of work? Moreover, the link takes us to FFT’s homepage, not a source for the information linked to the graph. My two cents - the optics will be better if the developer replaces that with original non-for-profit scientific sources.
More on scrutinizing FTP’s claim to fame as the “maximum” metabolic lactate steady state (this article was peer reviewed by a physiologist) : [Ron George: Functional Threshold Power : A Scientific Scrutiny](https://Functional Threshold Power : A Scientific Scrutiny)
Thanks for the nice tool David.