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Well. I think this is an easy assumption, but I respectfully disagree as I monitor heart rate decoupling closely and currently am in the 120-180 min range before seeing any sort of decoupling during a Z2 ride. My long rides are 3-4 hours.
I realize this isnāt the only metric for determining aerobic efficiency. A couple recent strict Z2 rides:
At the risk of further derailment, I have been doing all of my VO2max sessions (and current FTP sessions) based on a percentage of FTP (330w). So, itās odd that I can execute a 5x5 session at 120% of FTP (which is no doubt challenging), but am finding 3x15 @ 97% abnormally difficult. RPE feels more akin to 8-min @ 105%.
Iām chalking it up to accumulated fatigue and likely poor rest/recovery. Iāve been experimenting with non-traditional rest weeks, opting for more frequent 2-3 days of rest, I wonder if itās not working as effectively as I anticipated.
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Doh. Thanks - I guess I never kept a screen shot of that one (but I did find some notes).
Do you find the recommendations change much as you add new PRs to the curve?
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No need to apologize, Iām not debating what my FTP is and that wasnāt even the point of this thread, it just ended up going there.
My point was to see if anyone who has experience analyzing PD curve(s) could give some insight into what they use it for and how they use to shape training.
Again, not looking to discuss what my FTP is. FWIW, my last race effort (4 weeks ago) was 2 hour 40 min with an avg power of 293w and a normalized power of 322w. I think my FTP is well within the 310-330w range.
Depends on tte and what part of pdc you have improved. I basically do not use this chart that much for my workouts. For under FTP it is all the same for me, over ftp is always all-out in vo2 max. I do not train short power at all.
Iāve always used it to a) judge the results of training, and b) set interval targets. Can we debate your FTP instead? 
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@anthonylane why isnāt that race in the 42 day curve you originally posted?
I was filtering from May 30th to July 12th, and didnāt include that race result.
Hereās my 45 day curve (race was May 29th, 45 days ago):
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I rarely use Intervals, thought it was possible to use custom dates so you could do something like 90 days.
I imagine itās important to do some ātestingā and perform a range of efforts (say 5sec, 1min, 5min, 20min) across your curve to establish a baseline? Otherwise itās just modeling off your best efforts which could be A) not your best efforts B) old.
Can we debate your FTP instead?
By all means. 
I reckon itās not below 300w, and certainly not above 400w.
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You can, hereās 90 days. The thing it lacks is showing how you stack up amongst your peer group like the WKO chart.
I havenāt done any sort of testing since 14 April 2021 when I did some baseline measuring before starting a VO2 block. That consisted of max efforts of 5s, 30s, 60s, 4m.
It might be time to do this again in order to get clean and relevant data.
This bit stood out to me. I do understand that your 8min power in your power curve is lower than the modelled 8min power. However I donāt think that means you need to work on 8min power progressively, I think all you need is an all-out 8min test. The repeat intervalls sessions you have planned wonāt give you that, because you neccessarily need the effort to be repeatable. (Obviously, if you are still below where you want to be, and 8min is a meaningful duration for your events, work on it progressively as planned.)
I think in general it is a good idea to do all-out efforts of varying duration now and then, to be able to see your actual max ability power curve. You could pick one or two points per week on the power curve where thereās deviation from the model, and do a test on those. Over time, different durations will drop out of the time frame (42 or 90 days, or whatever you set), so you get to do max efforts over the whole range. (I believe wko has a handy āresidualsā chart that shows variation from the model more clearly, but you can do it with the intervals chart too).
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Hey @splash, thanks. Re: 8-min. This was just something I wanted to focus on in my second block of FTP work, with the other interval workout of the week being steady-state threshold w/bursts. I thought 8-min intervals could be fun, seeing as Iām prepping for CX and laps are around 6-8 min in duration.
The point of this block is to raise FTP from the bottom coming out of a really successful VO2 block.
FTP @ 320w (which I think is about right) is around 77% of my best 5-min power (413w or 129% of FTP). Which I think is too high, which makes me wonder if my FTP is truly closer to the 330w mark, and the recent struggles at 97% can be chalked up to just plain fatigue. Or something else? High anaerobic contribution?
FWIW, during my VO2 block in May I was targeting 390-400w for 4-5 min, which @ 320w would be 122-125%. Historically (4 years of structured training), working at percentages around 118-120% of FTP was my absolute max, and for periods no longer than 3 min.
This is quite interesting, we know that TR uses 70% of the highest 1-min power on a ramp test to calculate FTP (accuracy notwithstanding), but what if we use 5-min as a proxy. We can take 85% and for me that would put my FTP @ ~350w. Which I know isnāt possible. Interesting and possibly useless nonetheless.
Good call, this is something I should do probably bi-weeklyā¦or more often. They usually happen organically when Iām going after a Strava segment.
Thanks!
I also find that going for segments pulls a little more out of you than just hitting lap and going as hard as possible for x-duration.
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Exactly.
This is the conundrum I want to resolve myself, especially my numbers are almost identical. I have 420W 5 min power, 315-320W FTP but no sprint at all and my anaerobic capacity is more anorexic capacity. With those numbers and 1s 980W power (yes. I know you envy this amazing power) my mFTP is 318W in wko and 83% of vo2 max. As your sprint is way better your modeled FTP will be lower (around 305-310 I assume) and FRC higer.
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I went out an did some testing today. I started the ride off with a full-gas 90s effort (and subsequently secured a local KOM in the processā¦winning.) and then opted for a TTE test with a goal of going for 45-min. First time doing this outdoors, I ran into some trail blockages where I had to dismount, and then I had to fully stop a second time because my Garmin decided to shut itself off an restart at 33min into the 45min TTE effort. WTF!
Goals:
Test 10s, 20s, 90s, and TTE
Results:
10s: 1141w (model: 1046w, 42-day PR: 1202w)
20s: 1064w (model: 908w, 42-day PR: 1064w) 
60s (didnāt have a goal to test this): 654w (model: 649w, 42-day PR: 654w)
90s: 585w (model: 563w, 42-day PR: 585w)
TTE: 45-min (result was 46:38 @ 307w AVG / 322w NP)
Overall a pretty successful day out with some nice power-PRs. However, FTP definitely isnāt 330w, and I suspect accumulated fatigue and a ton of VO2max work has since forced it down. FRC/Wā is WAY up though.
What do you reckon my FTP is? 305 or 322 or somewhere in-between?
Curve as of today:
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