Dancing Skeleton

I have never done an official 20-minute FTP test, I've only had it calculated form 20-minute efforts while climbing Alpe du Zwift.

I have however done the Mt. Washington Auto Road Bicycle Hillclimb Race, and been completely wiped out at the finish.
This took aver an hour, and because the route is 7.4 miles at an average 12%, with no flat or recovery areas (it's pretty steady, some sections hit 18%, the lowest grade is 6-8%), it requires a steady effort.

I have my average & normalized power numbers (both very close) for the race, (263w/268w) & 20-min max (284w), my time was 1:12:22. My FTP at the time was 277w (from 20 minutes of a hard Zwift rode, 95% of 292w).

Is there a way to calculate my FTP on my Mt. Washington ride?

Thanks

WhyFi

What are you going to do with it?

Dancing Skeleton

Base my training zones on the number.
I used my FTP to train for Mt. Washington, and took almost 5 minutes off my previous time.
On that previous time, I had used my previous FTP for training.

Also, very few people actually have their FTP based on a 60-minute effort.
I had one of 72 minutes.

See where I'm going with this?

Thanks

tomato coupe

Why don't you just use your 1 hr power from Mt. Washington?

Dancing Skeleton

My maximum one hour during the race wasn't the max that I could put out in just an hour, if it had been I wouldn't have finished.
But I was completely spent at the end of the race, I had absolutely nothing left.

So my one-hour max power has to be more than my race average power.

Thanks

tomato coupe

I'd say you're splitting hairs. Pick a number between 263 W and 277 W -- it's not going to make much difference.

billridesbikes

72:22 is likely very close to one hour, you could just take 268W as your FTP since the personal power curve usually degrades slowly in the 1-3h range.

You could try interpolation since you have two data points: (292-263)/(20-72.37) = -0.554 and then (292+(slope*40)) = 270W. Not 100% exact since the total power curve it not linear and the ‘real’ FTP might be 1-2 watts lower than this as the real curve drops away in some power function.

I kind of expect the true FTP (power you can make in one hour) to be slightly less than the 20min*95% RoT number because the 20min effort include too much anaerobic effort as a percentage of the test IMO.

Seattle Forrest

Anything short of a perfectly paced 60 minute effort is going to be an estimate, and the numbers you have are very close. If the intervals are too hard or easy, adjust.

guachi

If you have Zwift, why not do a 20-minute FTP test?

jadocs

That’s how I do it, outside as well. I have found that 20 min tests tend to overestimate FTP for people who do not have the gas tank to go all out for an hour. It sounds like you have that conditioning, so 95% of your 20 min power is going to be fairly accurate.

Re: indoor FTP test: unless you are using your power meter (not trainer power), I would not put a lot of stock in your indoor FTP as far as accuracy.

Dancing Skeleton

I use my Favero Assima pedals for all of my power measurements, and use them to control my Kickr. This way I have apples to apples power comparisons from my trainer to my outdoor rides. I had figured that my 60-minute would be a little higher than my 112 minute, since after 60 minutes I still had something left, enough to finish the race strong. I'll take a 20-minute test sometime soon.

Thanks

aplcr0331

Just take an actual 60 minute FTP test. They’re much easier than 20 minute or 8 minute or ramp tests. Plus it’s your actual number.

Or just do a bunch of VO2 Max workouts and game the system via a Ramp Test. That way your fragile ego can remain solidly delusional.

See here;

https://www.trainingpeaks.com/blog/t...ing-protocols/

I made a couple of Kolies tests in Training Peaks. Best test of fitness by far.

Get your number the right way. Set your zones correctly.

Good luck.

colnago62

Ike this. There are so many variables. Get a number based on one of the systems out there and adjust if needed.

woodcraft

tomato coupe

Your 72-min power will probably give you a better indication of your FTP than using 95% of your 20-min power, as you will be doing less extrapolation over a flatter part of your power curve.

The 95% of 20-min rule is only an approximation to begin with, as it assumes everyone's power curve flattens in the same way. As per Training Peaks, it is a good estimate of FTP for about 50-60% of riders. It doesn't work for many riders, myself included. (My curve flattens quickly, and my 60-min power is 98% of my 20-min power.)

merlinextraligh

Your average power on Mt Washington is likely very close. You could argue its low, given the effort was a bit over an hour. On the other hand ftp climbing is typically a bit higher than calculated on a flat
effort.

I’d say those two effects pretty much offset.

On a practical note, set your zones off 263. If that proves too easy, up it.

Cypress

Your FTP is 267W.

I’m guessing you were climbing out of the saddle for at least a little bit on Mt. Washington, and in a normal FTP test being out of the saddle is shunned.

Additionally, the wattage difference in workouts between FTP’s at 263W and 270W is negligible, and you probably won’t be to hold a steady-enough power to know the difference anyways.

colnago62

I agree with the set and adjust as needed approach. You will know if it feels too low. It isn’t an exact science as a person’s numbers can vary due to the long list of variables that effect performance.

redlude97

FTP is not exactly an hour, coggan has always maintained it is about an hour. Time to exhaustion is 30-70 mins depending on your training level https://www.trainingpeaks.com/blog/t...ing-protocols/