# Category Enforcement - How is my category calculated? [February 2022]

Correct, and also the W’ threshold needs to be low enough to promote those riders that are winning so often with huge short duration power, as if you don’t promote these riders you actually have the opposite effect because their CP is suppressed (either accurately if they have true longer duration efforts recorded, or incorrectly if they don’t).

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they actually do calculate a specific value separate from W and CP though (i have no idea what method they use for that though, but the curve i understand very well), i think @Rich tripped it somehow and a staff member showed him the exact value (65.1?)

If I had to guess, and it would be a guess, I’d say they are using Hawley and Noakes with PPO at 6 minutes.

That dodgy CE table as regards VO2 and MAP is now posted at Zwift racing explained: categories, formats and tactics - BikeRadar

They do, but isn’t their idea of VO2 max just a proxy for the MAP value? It’s the same thing said in 2 different ways? (could be wrong and maybe they have added a 3rd dimension I didn’t know about)

Edit: apologies, I can see from the table linked above that they have indeed added a 3rd value! What is this supposed to achieve? And if it can be calculated from a single effort in watts, what have FirstBeat been doing for the last few years?

How can a so called VO2 of 60 push you over the limit, but also a VO2 of 65? Which one is it? It can’t be both!

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Continuing the discussion from Competitive & AI Tech Update: September/October 2022 Recap:

@xflintx I know you are busy with many things, in particular Race Scoring, but I wondered whether you have in fact had a chance to go back and check on the accuracy of the Category Enforcement FAQ chart values. Having different VO2Max figures in different columns is confusing.

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Im going to presume the chart is accurate, as Flint has been tagged in multiple posts highlighting that it might be inaccurate over a number of weeks and it remans as is…

So the 65 VO2 is completely irrelevant?

I have no idea if its accurate or not, my presumption is, if made aware a live document is inaccurate people would remove or update it… Its not been removed.

Benefit of the doubt etc…

Though @Rich was advised he had been promoted due to a Vo2 of 65.1 in the other thread

Further edit; @Rich Can you use that table & timestamp to look at the duration of the ZMAP value & ZFTP value

every vo2 max estimate i know of is fairly dubious but mine is above 60 and below 65 according to most of them

No they are using the new 65 VO2 figure. This was confirmed in the other thread when James informed @Rich that the reason he was CE Cat A was that he had exceeded the VO2 limit of 65.

Using Hawley and Noakes I believe yours might be around 70.

if it is then zwift isn’t using that method:

i’ve only looked at my garmin head unit and the golden cheetah method though (63 and 64.something respectively)

going from intervals.icu as you have seen, 382 was around the 6min mark which I’m going to guess was the socks4watts hill climb up the temple kom done on the 14th Oct which makes no real sense as i was still able to enter B races until around the 26th

We can conclude that by definition the table is wrong

What’s the point of the first column? Get out for when questions are raised?

Sam - are you saying that because you are not CE Cat A?

I believe you are doing your very best to hit over 65 VO2 and 5.4wkg MAP possibly to prove the CE chart works.

Whatever you achieve is not going to take you to CE Cat A until you can raise your FTP (95% of 20 min) to 250 or over.

Your ZP record shows your 95% at 241 and and FTP of 242 - so currently not >= 250

So using Zwift Chart

VO2 max = 70 AND greater than 250 - NO
MAP = 5.9wkg (approx) AND greater than 250 - NO
CP = 3.96 wkg (approx) AND greater than 250 - NO

(For CP I’m using your 3m, 6 min and 12 min power and High North 3 test at 100% goodness of fit)

Because of your very high short term power I don’t think any of the standard CP curves or calculations are going to take you anywhere 4.2wkg to exceed CP limit.

So unless you can put in a 20 minute ride with an average of 264 or above I don’t think you are going to exceed the CE limits.

The reason IMO is all due to the fact ZWIFT is using AND >= 250 W with each criteria.

VO2 Max and MAP might well be working for heavier riders (because 95% of 20 min is already over 250W) but it is not working with lightweight riders.

If having a VO2max above 65 or having a MAP over 5.4wkg is supposed to be good enough whether you or heavy or light then ZWIFT just need to remover the AND >= 250 from each of those two criteria columns.

Apologies if I’m a million miles off the mark.

EDIT : After seeing reply. The 250 W may not be FTP but CP.

i am trying to understand how the CE system works, not because i want to prove or disprove anything but so i can 1: explain to people why I am B and they are A and 2: give practical advice to people who think they are unfairly categorised, because i feel sympathetic towards them.

it’s true that the highest 20 minute i’ve managed since January is 261w. but I have actually been CE A twice since, both times as a direct result of two separate 10-12 minute efforts

so my speculation they are using two points on a curve and the algorithm is probably not much more complex than that (3 and 12 mins… bear in mind they have to calculate this daily for every single person who uses zwift, thinking about it practically, it can’t be too complicated)

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@Ian_Attoe posted a table in his post above which makes more sense. This may be what Zwift are actually using, they just struggle to communicate it without typos:

And I agree with him, when they update their table they should show it this way with the scribbles and arrows

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Reading this makes me rethink my 250 W comments. If you have not been above 261w for 20 min then you could never have been above 250W FTP.

Also reread the original post and again notice that the 250 has CP written after it, which I had clearly forgotten over the past 8/9 months.

Do you know if you have been above 250 CP or eFTP on Intervals or by your own calculations and if so do they tie in with the two occasions when you were CE Cat A?

I agree Zwift may well be using a 2 point CP calculation on 3 and 12 minutes and if at anytime you had 3 min power of 325 and 12 of 270 that would have taken you just over 250 W CP.

Checking for dates and power more than 60 days ago is difficult on ZP

Re-reading some of the posts in this thread I found this post from @gloscherrybomb from back in February which I think hits the nail on the head very well.