FTP Question


(C lau) #1

I took an FTP test yesterday, but there was no message at the end of the test. My previous ftp was unchanged, 175 W.
I suspect this happened because I paused it at the beginning of the 20 minutes to change gears.

From Strava I see that my best 20 minutes were 192 W. Is this the number I should put manually as my new FTP, or do I have to reduce it by some factor to reflect a 1 hour effort?

Or is this why the ftp did not update, because the results weren’t good enough?


(Evert Herremans) #2

You should multiply your best 20-minute power by x0,95. Meaning if your best 20minute effort is 192, your FTP should be ~182.

However, that being said… always make sure your best 20 minute effort is an evenly paced effort, and the tank is completely empty after 20 minutes. Otherwise your FTP value will come out wrong (too low).

Power/effort ratio is not a linear thing which is why it is important to keep roughly the same power for the entire 20mins.


(Aaron Zwanzig) #3

“or do I have to reduce it by some factor to reflect a 1 hour effort?”

Yes. Your FTP is 95% of your 20 minute effort.

Based on your 192 watts effort, your FTP would be 182.

Here is an article discussing FTP within Zwift:
https://support.zwift.com/en_us/what-is-ftp-and-how-is-it-used-in-zwift-SyeLlRkbBm


(C lau) #4

This clarifies a lot.

Thanks Evert and Aaron :+1: