How does that apply to Zwift?
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The 1.79 update included rolling out the calculation used for The Grade to any activity in any location.
Any PB from 8 to 60 minutes can trigger a new FTP, with the percentage changing depending on the length of the PB interval.
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No zFTP is a modelled/estimated FTP, FTP in zwift is your training FTP used to set zones. But what OP and I donât get is why our modelled FTP (zFTP) went down after a >12 min effort. I understand why and how an effort <2-3 minute could lead to a lower modelled/ estimated/ z FTP because it means your anaerobic capacity is apparently bigger and therefore able to contribute more but I donât get is how a longer effort is able to do that.
I presume itâs because your 2/3 minute power, as it relates to your longer-term power (20m+) just became lower (flatter curve) on a relative basis.
With the reset of my ZRS to zero and the ensuing rise to 254, my zFTP went from 275 to 175. These changes are because my new trainer is not as optimistic as my previous unit, hence the reset. Itâs going to be interesting when I finally start workouts to see if I need to lower the Erg percent offset like I did right after getting the new trainer.
I donât think Zwift have revealed which model theyâre using for zFTP/CP and so itâs possible theyâre including a data point out past 20 minutes to feed the model.
We also donât know what other efforts may have moved in and/or out of the 90 day window to feed the model since the OP last looked at their zFTP.
Overall, as I tacitly implied earlier, I think zFTP is ⌠not necessarily a great metric, so my capacity to care is somewhat constrained.
Iâve been on zwift around 60 days, so no efforts moved out the 90 day windows yetâŚ
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Question concerning the power graph visible on the bottom of the screen when you press âGâ.
That graph shows your power zone (and obstructs seeing the distance to the racers behind you).
My zFTP is somewhere around 225.
I set my FTP for workouts around 240 because that is my optimistic goal for this year.
Are the zones based upon my zFTP or my made-up FTP?
I still would like to see the distance to the riders behind me.
Same issue with the new elevation graph by the minimap.
It obscures the dots behind me.
Theyâre based on your inputted FTP and not your zFTP. My zFTP is way lower than my actual, which Iâve manually entered in, and the colouring of the graph matches the correct zones for my inputted FTP. Iâd be curious if anyone has calculated what percentages theyâre using to calculate those zones though.
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In your shoes Iâd chalk it up to âZwift Doing Zwift Thingsâ and forget about it. Itâs just noise at this point, imo.
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Thanks for linking that summary. Now, can anyone suggest a reason that Zwift is using their own system, which is different than everyone else (eg. Strava) â namely the Coggan levels? Is it just Zwift being Zwift?
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Coggan doesnât even use these zones anymore but instead switched to ilevels which are zones individualised to the athlete
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Market differentiation? Copyrights? And have you ever seen an engineer who, given the opportunity, could resist the temptation to invent their own method?
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Maybe just rounding up to nearest 5% increment like in workouts. Had to reuse the workout code rounding.