FTP test is funny

And not as in HAHA funny but really a bit of a joke. I did the 4 week FTP booster and the last day is, yes, an FTP test which is good since I would be interested to see any increase/decline. Well I spend the > hour to do the test and during the actual FTP part (20 minutes) I keep the power above what I know my current FTP is. Weeeeelllll above so I’m really chuffed giving some extra motivation for the last few minutes, except…

a) I get NO feedback at the end except for the normal workout completion. I was expecting some sort of comparison between my condition at the start of the program and the end. 

b) Since it did not say my FTP improved I would only assume that it did not. Looking at the workout afterward it indicates a WELL below my previous FTP performance. Somewhere in the region of <25%. This is true only if you take the warmup and cooldown periods into consideration as most of this is 50% or less of the current FTP. I know for a fact that I never once dipped below the current FTP, staying at least 10-20W above it, yet the end result is ~80W below.

While I know I’m stronger than before the start of the 4 week program the feedback at the end is very disappointing, and that is being kind!

Your FTP is 95% of the average of the 20min section. 

If you look at your strava data you can select only the 20min section and 95% of that should give you your FTP. 

If your FTP was 190w and your average watt was 199 then you would not see a increase of FTP. (190*0.95=200w)

You misspelled “hard.”


Not sure what Joe is on about but thanks for the contribution :wink:

Gerrie, yes 95% of my average over the 20 minutes is 0.5W below my current FTP i.e. I did not improve it during the test. But this is not my actual issue. As I mentioned, the feedback from the workout is less than ideal because:

a) The purpose of the program was to boost FTP. This I actually did because my FTP increase by ~20% from when I started and Zwift updated it whenever I showed improvement during the 4 week period. But at the last workout of the program there is absolutely no feedback re the effectiveness. It simply ends like any other workout.

b) The purpose of an FTP is to test the FTP right? Well, it then makes absolutely NO sense to only report back on the overall average power, which included more than 50% below threshold effort as part of warmup and cooldown. This is like doing a race and then reporting on my position in the starting chute as the race result.

Hence my subject line.

I think I understand your question a bit better now. My guess is that the FTP test in the 4 week FTP builder is a bit different from the 2 FTP tests that you can do in ZWIFT. There fore it did not show the screen indicating that you increased your FTP.


Also I think since your FTP was updated during the 4 weeks you would have a high FTP when you started the FTP test and there fore it will compare before the test and after the test, not from Start of the 4week program.


20% FTP increase is awesome! 


Wow congratulations on the improvement!

Gerrie seems to have the answer; if you search https://whatsonzwift.com for FTP workouts you’ll see a bunch that were put into training programs. Zwift may need to add the features from their main test over to the others (toggle for workout creators or similar).


Yea I’m super impressed with the result but I guess the lower you start the more room you have for improvement :wink: This type of improvement probably won’t come along again soon :(. 

I think it will be great to get some summary of progress throughout the program instead of such a blunt ending.

Thanks, Matt I will have a look at the link.

As an additional note i always fire up the garmin and record just the 20 minutes of FTP effort as an individual file.

This then gives me the average data for that 20 minutes and i do my own calculation to ensure that the zwift one is accurate.

I end up with a zwift workout for the entire session and a garmin file for the 20 minute test which is handy for comparison in the future.

You can always just download the .fit file for the ride from Zwift.com and open it in any analysis software you want, including uploading to garminconnect.com - of course, if you want to see if Zwift is accurately recording the same power data as the Garmin head unit I suppose it might be worth doing to convince yourself there is no systematic error going on.

I thought the FTP test was 90% of your maximum 20 min effort.

I believe you can do it anytime.

I recently had to make trainer adjustments and want to get an updated FTP before I start riding outdoors again. I only like to do one hard work out per week so today at the Watopia Tour, I set my FTP down by 100 points then I after warming up, I rode a maximum effort X 20 min (actually 23 min just to be sure).

My new FTP was calculated.

I think I will do this once a month or so, when ever I’m going to ride hard.

Otherwise my FTP becomes my historical “best” 20 min effort and may not reflect my current best.

Has anyone seen zwift auto update their ftp? When you exceed your previous best 20 min power it auto updates. This happened during a race when I was hanging tough with some strong riders. Seems a strange way of doing it. A race will be full of surges so the average may be higher. Not the same as pushing out 20 consitent minutes.


Yeah, I’ve had mine update like that too. It really doesn’t matter if there are surges or not. The FTP test takes the average over a 20 min effort and it doesn’t matter if you’re rock solid throughout, or if you go hard for 5 min than fade, OR if you start slow and ramp up as you go. There are lots of strategies for taking the test - but in the end? All that matters is your best 20 min avg.