It’s different in the sense that zFTP is an estimation coming from your current power curve data analysis (last 60 days). It assumes you have done maximal efforts. If you haven’t, the estimation will not be accurate.
FTP is the value that either you enter manually, because you know the value (field test, laboratory test, etc.) or that the Zwift game returns after you have done a ‘formal’ test (20 min. power or Ramp test). So it’s basically the value that you want defined on your profile, that you assume to be correct.
In case you have done maximal efforts within the last 2 months, in a variety of durations, ranging from 30 seconds to at least 12 min., we encourage the user to set their FTP to the zFTP value.
Thank you and that is very helpful. But since Zwift does do a regular FTP estimate as well, I am not sure which one I should be using. The last time mine changed it was 210, but my zFTP is 233. If you are saying we should change our workout screens FTP to what the zFTP is, it means there are three competing systems on Zwift: A real FTP test, an estimated FTP, and a zFTP.
This changes things a lot for me. So as I understand it is the zFTP is a calculation based on scientific research (probably a paper that we can reference) to determine FTP using more various data points on the Power curve.
the “real” FTP that you determined with a test (or that you know from other source) and that you can set on your profile or is set automatically after a test on Zwift.
Occasionally after a ride, not necessarily a race, there will be a message that your estimated FTP has changed. The workout slider changes to reflect this number (that’s why I started this thread). The last time I saw that message, it was 210 (I think). But that number is not the same as zFTP.
zFTP is determined based on several points of the power curve, sometimes starting in 5 min. up to 40 or 50 min. (or less) depending on what we determine is the best maximal fit for the curve.
if you haven’t done maximal efforts of at least 12 min. within the last 60 days, then you shouldn’t consider it accurate.
Calling it something that doesn’t include the letters F, T and P (in that order) means that people are more likely to look to see what it means than simply making an assumption because they’ve heard a very similar term before.
Define an all out effort?
A race effort will rarely be all out for 12 mins as it is to on/off (NP maybe but its not measuring that)
TT effort maybe - but how many TT efforts are 12 mins.
Is there a 12 min protocol? Coopers test in running, im not sure if there is one in cycling.
FTP done with an actual FTP test, or input by the user.
Zwift’s estimate of your FTP based on just riding around (which updates your FTP for workouts - this is the one that gives you the “you’re FTP is updated” prompt, but is not based on an actual FTP test)
zFTP which uses multiple points on your power curve based on your stored data. This does not update your FTP for workouts etc., but will be used for Category Enforcement.
I don’t think so - #2 is really not going to be set via a max 20 min effort for the vast majority of people (unless they happened to do it on a 20 min TT). So, if someone is using #2 to set their zones it’s probably the least accurate of the 3.
