Does the same apply if the 5 minutes power is very high compared to FTP as well? Or is it limited to efforts close to 1-2 min?
Out of curiousity, how does your 5 min power compare? I noticed my eFTP recently was slightly off compared to the mFTP provided by WKO5 (the latter recommended a lower FTP). My 5 min was 323W and WKO recommended an FTP of 229W. I know it is based on what I have as data for WKO (for which I had plenty of data) but was surprised eFTP from intervals.icu was suggesting 263W. I like to use 2x20 to validate my FTP. A workout like Gray for example is what I used (although I think maybe the rest in between is a little low).
I can’t specifically comment on using the single 20 minute duration with no clearing effort (to remove the anaerobic contribution), but your FTP floor (the lowest I would set it to) should be the average of the 4 blocks in Lamarck (don’t include the rest in between).
btw, good job coming back so strong after your surgery! Hopefully you beat it!
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Gray looks a good Work Out 
My ramp test 5mins back in July is my record for this year it was 321w, eFTP was 266w Ramp test FTP was 265 quite accurate on that ride. My last ramp test on Tuesday was 286w, the eFTP was 256w and the ramp test FTP just 238w. Quite a difference 
With ERG turned off at the start of Thu session for 5min I was 287w which is similar the ramp test number, eFTP was 256w for that and the 46min NP (probably as close I’ll get to a hour test) was 250w.
I’ve hopefully beaten my personal C thing now; my last chemo was the End of Oct last year, and by February I’d built my self up to a 20mins max of 296w. Then the other C thing hit the world. I held the w/kg for a while and actually increased it to 5w/kg through not constantly snacking. A stressful period then constant snacking has seen me lose it again and I’m sitting at 4.37w/kg, if the 250w 46min NP is an accurate reflection of my FTP. I just need to patiently rebuild it I think.
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Anyone on a Kickr? I wonder what the variance is for the trainer given the lies it broadcast on erg? +/-5% (toss in the hat) plus 2%ish trainer accuracy, that could be your difference.
I thought eFTP was FTP on an e-bike? In which case mine’s like 900w.
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Probably the same applies. The longer the test period the less your anaerobic side skews the results.
e-FTP for the win!
I don’t think that is correct. To fit a 3 parameter model, it would need to use at least 3 points. Doesn’t it use only 1?
The ‘standard’ 45 minute warm-up is the Hunter Allen protocol, and includes the 5 minute max effort.
From the website:
- Power modelling using Intervals.icu’s own algorithm (eFTP, predefined curves and Mortons 3P), Morton’s 3 parameter CP model or Monod & Scherrer’s 2 parameter CP model
From forum.intervals.icu here is a comment from David the developer:
So single max effort and mapping that to a predefined curve (from a family of curves).
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Yes it only uses one. But it picks from many real power curves modeled using Morton’s 3P. So everyone who can do 330w for 10m gets the same curve and FTP. This works well for longer durations. For short if you are good at that it overestimates and the fix is to bump up the min duration for the estimate. It uses your real pMax.
I am going to do some work soon to use the short durations to try estimate W’ to complete the picture.
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Isn’t that really just using one curve, and merely adjusting the whole thing up or down?
To state it another way, aren’t you assuming that for any given duration, everyone can maintain the same percentage of FTP?
Not what I read. Let’s say you have data on thousands of athletes. Use Morton’s 3P model on all athletes. Then reduce the number of curves down to say 20. Those are 20 unique power duration curves.
Now a single max effort gets mapped to one of those 20 curves.
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Yea, I think a lot of people may just not realize that - and newer cyclists especially may be more likely to have blowout 3-5 min efforts from Strava and few to none 20-60 min efforts - giving a lot of people inflated eFTPs that are not useful for training. It’s the same concern I’ve seen with the ramp test and new cyclists who may not know a realistic “offset” to use if they’ve been training anaerobic efforts hard thanks to segments, or no real endurance capacity.
Moving the setting from 300->600 secs gives me a FTP that is more realistic, as does using either the 2 or 3 param options. And going to 180 secs gives me a FTP I only dream about 
The eFTP seems to be sensitive to even a 10% difference in how your short vs. long power compares to the “average” cyclist’s power-duration curve. So unless you are really flat at same relative % to other cyclists across the durations, it’s probably very risky to use eFTP.
But this is the really nice thing you have that TR does not yet have in the ramp test analysis - you can actually see if someone’s power-duration curve is “abnormal” in shape/percentile relative to the average of all riders, and warn them before they crash and burn with that value!
Something like “hey, we notice you are disproportionately strong in 3-5 min power - be careful using eFTP!” Follow-up to such a user could include suggesting that they perform a 20 min maximum effort, and/or check the value using the 2 or 3 parameter model after such an effort exists, etc…
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Cool, I agree that should tell you a lot - I’ve also been doing 10 mile TTs most weeks this season and it’s given me a lot more confidence that I know where I’m at for FTP to the point that I have stopped doing ramp tests or relying on other extrapolations - and I now want to try the Kolie Moore style test as the next step to confirm how long can I do 95% of my 10 mile TT power!
Let us know how it goes!
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Never pushed that hard in the end. I got a 19s PB (if my Garmin is to be believed). I think I have a mental block when it comes to pushing to the edge on a busy dual carriageway 
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or they only do indoor trainer workouts and have no max efforts.
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I feel seen.
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I don’t think it works that way. In fact, it can’t work that way, because one point could fall on any of an infinite number of curves.
Well I limited it to 20 curves so it can’t be infinite number. I’ll think about it some more.