Fatigue or wrong FTP calculation by Zwift?

Hello fellow Zwifters!

I am rather new to zwift and started off with a really poor shape, after a little less than a year in cancer treatment for Leukemia. I decided to take up Zwift after trying my brothers Road Cycle outside to get back in shape, and I found that I really enjoy it, so now I really wanna get good at it and do long distance riding!

So, to get on the topic. I’ve been zwifting for about a month now I think, nothing massive and between 4-6 times a week, depending on my schedule. I have not been following any exact training plans and have just participated in group rides on the tour for all and done random routes I thought looked nice and tried to see how far I could go. I usually ride about an hour per session, +/- some. As you can probably tell, my training is not very structured whatsoever. However, I do go hard, every time, I aim to be toasted after each session.
So I decided to start an actual traning plan, because I wanna get good at long distance riding, I picked the Gran Fondo plan. Now, I obviously wanted the workouts within the plan to be as accurate as possible, so I decided to do a ramp test. Before the ramp test, Zwift had put my FTP at 224, and after doing the FTP Ramp Test, it was 271. A rather drastic increase. That was yesterday. Today I started the first workout of the Gran Fondo plan, the Long Tempo workout, that had 90% FTP intervals for 3 minutes, then 1 minute rest x 10. However, after the first 4 intervals, I was exhausted. Literally could not pedal harder than 150 watts. And I felt like I did everything right, I planned ahead, set a good pace of 90 RPM, got good amount of food in the day prior and a couple of hours prior as well.
So my question is, did the ramp test overestimate my FTP by a lot, or am I just fatigued and need some time off? As a former amateur bodybuilder, it seems very unlikely to be fatigued after a month of cardio, that isn’t even on a daily basis, but obviously I don’t really know much about it, which is why I decided to write here!

Thanks for any response!

Most likely it did, ramp tests are more of a VO2 max test rather than FTP. I would suggest doing the short FTP test and see how it compares (after a good rest day or two).

Recovery and rest are just as important. I’ve heard coaches say that on hard days sometimes people don’t go hard enough and on easy days they don’t go easy enough.

Good luck with your training!


Curious, what type of trainer are you using, wheel on/off, smart/dumb?

224 to 271 could be a drastic jump or not depending on how many weeks or months have passed between those numbers, what type of training you have been doing, etc…

When did you do this workout, AM or PM? What did you do the day before? Were you fasted? Did you fuel and hydrate during your workout?

Most of that is answered in my post. I use the Tacx vortex smart and I always fuel myself for training, and train around the middle of the day!

Do you set your trainer up the same each time (i.e., same tire pressure, calibration, etc…)? If not, that could noticeably affect the accuracy of your power numbers.

The other option is that you had a bad day. It happens. This is not a problem until you start having a lot of bad days.

Did you make sure everything was set up the same? I mean tire pressure, calibrated trainer etc? The vortex smart is not the best for consistency (same problem with other wheel on trainers) and this can make a huge difference. I would ensure you set it up as closely to exactly the same before any FTP test then again for your first session each week (if not every session). This protocol has worked well for both myself and my sister using this trainer, both of us having had similar issues to what you are describing.

The other side of things is that structured training is hard! Coming from completely unstructured training to structured training will be a shock and I’ve seen others comment that the zwift plans are unforgiving (though I haven’t used them myself…I’m a TrainierRoad user instead).