I would love to hear Dr. Coggin chime in on this thread. I am not suggesting that you can back-calculate FTP or anything like that. What I am saying is that by definition, the 8-minute test is 111% of FTP for 8 minutes (x2 with a long recovery). Yes, there is warm-up and stress before the 8 minutes, but at a high level, it seems reasonable that the 8 minutes of that test ought to closely correlate to what a rider could do for 110% (as the OP asked), given reasonable warm-up ahead of time.

Last year I estimated my FTP to be around 300w and did 330w for 22:12 during an uphill TT on my road bike. I was shooting for around 315-320, but 330 felt okay early on and I just stuck with it. Did the normal back pedal on my quarq before so I think it was reading okay. The end result fell in line with what I would have expected given my weight at the time as I have done that climb about 500 times at various weights and power.

Could have been that my FTP was a bit higher than 300, but in general my power curve is generally that my FTP is about 92% of max 20' effort. Being able to sit up for the most part (average grade was 6% so aero wasn't that much of a penalty) and having the uphill resistance definitely helped in squeezing out more power compared to an effort on the flats.

I don't think Nate was prescribing anything, Seemed like he was curious of other peoples experience with similar efforts.

I have done the same indoor TT as Nate for a while now. Last year i think i went 17:15 at 283. 3 months later I did an 18 mile uphill TT and held 265 65minutes. So around 93%. Very consitent for my N=1.

i regularly do repeated 8 minute efforts at 110% of my estimated FTP.
For reverse corroboration, XERT confirms my FTP estimate based on those efforts
Garmin estimates my FTP as 10-15W lower.

on a good day i can average my estimated FTP for 20-25 minutes, i would need to be incredibly motivated (chased by a lion) to get anywhere near the theoretical ability to hold FTP for 60 minutes

I've done 20 mins and 21 mins outdoors up a mountain twice in the past. Those were full-on, max efforts I couldn't replicate weekly, though.

If you are aerobically inclined, then you're not going to be able to do 110% for all that long. But good news, estimating FTP at 95% of 20min power may indeed be relatively accurate. If you fall in this category, your 110% duration might be as low as 6-12 minutes.

If you are anaerobically inclined, then you will be able to do 110% longer than your aerobic counterpart. But bad news, estimating FTP at 95% will overstate your FTP, it's likely closer to 90% of 20 min power. And in this case, the math is easy enough and you can do 110% for 20 min or so.

Personally, I am in the latter group. I would estimate my 110% at 20 min, maybe a little longer. But I also know that I can't multiply my 20 min power by 0.95 to get FTP, instead it would probably be more like 0.88 or so.

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Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

Was at an indoor session a couple of weeks ago, being run by a coach who has several pros on his books, mostly WT level. He said that he has encountered only one rider in his career whose ftp was 95% of 20 mins.

For me - about 91% would be the best estimate.

Same here for me. My recent best hour AP is 278 and best hour NP is 310, both yesterday. From these, Xert puts my FTP in the 290s, WKO4 just a little bit lower. My recent best 20 min (a few weeks ago) is 316. So for me it's probably somewhere in the 89 to 93% range.

I can hold 110% FTP for an hour.

I am like a Spinal Tap amplifier.

The simple answer is here https://goo.gl/zRGui8 one of our calculators will work in out for you (personalized to your watts)

The complicated answer is that it depends........

1. you didn't specify 110% of what?
2. assuming you mean FTP hardly anyone can agree on a gold standard FTP test without shouting at each other about "deadly sins"
3. assuming you have done some kind of robust 60min test enough times to get your recent best then you probably already know the answer from your shorter rides vs 60min
4. assuming you have done a protocol based 20min test then the 95% rule has proven to be accurate only in 7% of athletes (usually at the top end of ability)
5. Even with the above, the power-duration curve is actually never linear, and quite personal and has a slightly different decay shape depending on your current FTP.

Having said all that our calculator does a pretty good job of predicting event power from FTP and you can enter any time and any distance and get an answer

Hope that helps someone

regards