More than 90 days ago I reached a certain level and my zFTP was set accordingly. However, due to circumstances I didn’t reach that level anymore. Now, after 90 days, my zFTP did not change in regard to my new power numbers.
In other words, my powernumbers went down but my zFTP stays the same even after 90 days.
If you go to The at Home Cycling & Running Virtual Training App and scroll down a bit the right side will list your best power numbers for the last 90 days.
If you can check they show correctly first look more so at the higher time frame numbers to see if they are similar to zFTP
They are not in line with my zFTP. zFTP was set to 310 based on 335 for 20 min, more than 90 days ago. Now my best 20 min power is 283w and 40 min is 257w. But my zFTP is still 310w.
If a high 5 minute PR recently expired, that will tend to inflate your zFTP, so if say 20 min went down a little, but 5 min went down a lot, that will result in a higher zFTP relative to your long term power numbers.
If you want to talk to support about it, email zwiftpower@zwift.com
That doesn’t make sense at all right? Okay my 5 min power dropped as well. Due to illness my fitness dropped significantly over all timeframes, being it 1min, 5min, 12min, 20min, 40min my peak power the last 90 days dropped significantly.
However, my zFTP is still 310w, just like more than 90 days ago. While I think it should be corrected to my new fitness/powernumbers.
Sounds like you should contact support and see what they say. I’d be interested to hear the outcome.
I’ve sent an email, will update this thread with their response. Still, hopefully someone will reply with the solution instead.
You aren’t looking at zFTP on ZwiftPower right? That can be out of date (hit refresh profile to pull the current number to ZwiftPower). But the number you see in the Fitness section of your feed (my.zwift.com) should always be pretty fresh.
Other than that there’s nothing you can do if you’re running into a bug. The whole point of zFTP is you can’t change it. I have heard of bugs in Category Enforcement a few times but they are pretty rare and always have to be handled by support.
From my experience, zFTP and zMAP won’t update to lower numbers, despite higher numbers being from over 90 days ago, until I do a ride greater than 90 days after the old numbers came into force.
I can’t remember now whether you have to get within a certain percentage (20%?) if your old numbers, for a ride to give you new zFTP and zMAP figures.
it recalculates that stuff after (well, during, but it will update after) your next ride, so if you haven’t ridden since your numbers were supposed to have dropped, it will do it then. i think the ride has to be at least 5km or something, also.
if that’s not the issue, then it’s one for zhq. i’ve never seen it before
Thanks Steve and SA, I did a ride, stayed 20+ min above 80% of my previous zFTP to be sure and it worked. It updated my zFTP accordingly.
Zwift support answered my email as well but they forwarded my inquiry to ZwiftPower support and they were rambling about some tool to delete previous results from ZwiftPower or something. Zwift Support clearly doesn’t know their own product 
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