Difference between zFTP and FTP?

On ZP, it says that A+ requirement is 300FTP. But on my profile page, I only see zFTP. Are these two numbers the same?

And how is the FTP required for upgrade calculated? Is it 20-min power or 40+min power?

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Hope this post from 28th March help explain the situation.

it was pointed out this would cause confusion

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It does clear some things up, but I’m still unsure whether 20-min efforts are enough to boost FTP, or if it will have to be longer than that. But the answer will probably vary with the individual power curve of the riders

A+ isn’t a category from the CE perspective and doesn’t appear in the table of values that they published about the CE boundaries, so I’m unsure if the old info about A+ on the ZwiftPower site is still accurate but I assume it’s based on the zFTP curve now. Exactly how the calculation works is a secret, but it’s easy to end up with an inflated zFTP by doing only long efforts, not doing MAP efforts. A rider who does that will sometimes end up with a zFTP well above their actual FTP. There is no single amount of time needed to calculate zFTP. A rider who never stays on the bike for 20 minutes would still have a zFTP value calculated (but probably not a very accurate one).

Cheers for the input. I found out today that I should be pretty close, so I’ve decided to give it a go, but I dont want it to interfere with my races, so I’ll just have to do it the hard way (as opposed to doing it by also limiting MAP efforts)

I’d start by beating the 30 minute PR and see how that affects the zFTP value you see on your profile on my.zwift.com. Maybe a TT or pacing a 30 minute effort up the Alpe. That would probably* flatten the curve the most.

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I’ll go for that. Should be this one, right?

Yes. Looks like a good time to go for it since your 90 day fitness is as good as the game has ever seen it. Pretty much all tops.

Well, I punched it up the Alpe for 30 mins and improved my 30-min power. Recovered for a while and punched it a bit towards the top when I saw that a new PR was within reach. So the whole thing also improved my 40-min power. And my zFTP is now above 300. Still red, though.

ZwiftPower only updates when you do an event so maybe if you hop back on for a quick race now…

Well, it did update my FTP, so I am more inclined to think that the requirements are just tougher than I initially thought. My FTP probably needs to be above 4.6wkg as well (which isn’t quite the case even with today’s improvement).

Hey @Thomas_Sorensen_eCKD I swear I’m not stalking you all over virtual-zwiftworld though zwiftpower does say you are on my list of nemesis :wink:

Curious in the end what you learned here with regards to duration-of-effort, whether it was 95%-of or 100% of the effort, when zwiftpower updated after setting a new power, etc? I recognize (and can verify from looking at A+ riders on DIRT with <300W “zwiftpower 20min time” that it’s based entirely on zFTP calcs (where those <300W riders do have >300W zFTP) so it’s a little bit of a black box…

I find myself in the same position you were late last year where fitness-wise getting the spiffy A+ tag might be in reach as a kind-of-silly goal and I’m thinking about it. Would be especially cool if I could do it while at altitude but will be borderline for me so need to engage brain and legs.

Thanks in advance :slight_smile:

I never found out which specific interval was the best for boosting zFTP, but I can say that in each case where I’ve been upgraded to A+ it’s been on the back of a hard run up the AdZ. So 40-min power definitely has an impact on zFTP.

The limit seems to be around 4.6wkg (which I am fast approaching after I’ve started regaining the weight I lost for the nationals without adding power - so maybe our victim/nemesis roles will be inverted before too long :wink: