KEY TAKEAWAYS
This is a conversation I have wanted to have on the podcast for a long time. Dr Phil Skiba is the exercise physiologist who put the W' model on the map for cycling, and sitting across from him for over an hour was a proper masterclass in how power really works.
Most of us think about performance through the lens of FTP. One number, one test, and your entire training plan built around it. Phil makes a compelling case that this is incomplete. Critical power and W' give you two numbers instead of one: the threshold you can hold indefinitely, and the finite battery of work you can do above it. Together, they describe your performance in a way that a single FTP value simply cannot.
What stuck with me most was his explanation of W' reconstitution — how that above-threshold battery recharges while you ride below CP. The rate at which it refills is not fixed. It is trainable. And that has massive implications if you race criteriums, road races, or anything where repeated surges decide the outcome. Two riders with identical critical power values can perform completely differently in a race if one of them recharges W' thirty percent faster.
We also talked about testing. The CP model requires multiple maximal efforts at different durations rather than a single twenty-minute block. Phil walked through exactly how to run the protocol and what the numbers mean when you get them.
If you have ever felt that FTP does not quite capture what you can do on the road, this episode will give you the language and the framework to think about your power data differently.
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