I got my first power meter a couple years ago during the fall and spent all winter training indoors with it. I always heard that power came easier outside. When I finally got outside with it, I was hugely disappointed in how hard it was to apply power on the road. On the trainer, you have constant, consistent resistance. Outdoors you don't. After a month or two riding outside more frequently, indoor and outdoor PE started to match power more closely, but it took some getting used to learning how to apply power outdoors. I don't think trainers simulate going downhill, or riding with a strong tailwind, where you really need to stay on top of the gear to maintain power.

In a race, the course and race dynamics play a big role in how you can apply power. If you have a lot of turns, that is going to effect power. If there are a lot of steep downhills, that will effect power. Other athletes will effect your power as you are trying to remain draft legal and pass legally. In training, particularly on a trainer, your goal is to hit your power targets for intervals. In a race, your goal should be to ride as fast as possible expending the least amount of energy you can.

My guess is that you riding around .84 instead of .92 can be chalked up to less time outside for early season races PLUS the race course and race dynamics.

I think you're correct on how Zwift determines FTP. However, after looking back on my power output for this race it showed that I averaged right around 4.1 w/kg, 270 watts. This was for the entire race with only 3, one minute spikes (I think I remember getting dropped from the group and just pushing steady alone).

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Dominic Pollizzi

This is spot on for my situation. Thanks!

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Dominic Pollizzi

Is this your average or normalized power? I know with my power meter/head unit that I use, anytime that I'm not pedaling the power stops recording, thus dropping the average power fairly significantly. I've read their is ways to turn this zero averaging on/off but I haven't cared enough to play with it. I tend to go off normalized power since some descents on my rides I have to coast due to the windy/sharp turns, thus dropping my average power.

Yes, this was normalized power. Average power was 222

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Dominic Pollizzi

You shouldn't turn off zeros, because zero watt times are rest times. At stop lights, sure, but not for normal riding

If you had, say a 5 minute descent where you freewheeled and a 5 minute flat where you are pushing 200w and you turned off zeros, then you would get 200w average. If zeros were still on, then you'd get 100w average, which is more representative of what you actually did on that ride.

This is nearly identical to my experience as well. Riding on a trainer is like riding on pancake flat roads with no major turns. When riding outdoors power is much more variable. What really helped me was staying on top of my gear changes approaching the tops of the rollers and over/down the backside. This is also easier if i used some discipline at the bottom of the hill keeping that effort relatively close to overall power target.

Although if you're comparing zwift there are some grade changes in there, there's also thr factor that there is almost no upper body engagement indoors which lowers hr/rpe slightly.

Where I've done a pancake flat 10 mile (16km) time trial, I can average 315 watts (which was 315w normalized). On a slightly hilly course (roughly 50m elevation, but otherwise the same out to a roundabout and back, no turns), I average 300 normalized. I'm pushing 10% harder up the hills. So that's a 5% difference.

So combine that kind of difference with the roughly 90% FTP you'd expect for an Olympic, you're no that far off I guess.

Do you calibrate your power meter before riding? I've got a crank based one and the temperature (cold evening turbos and hot daytime races) makes a big difference to the readings if I forget

Enjoy reading about FTP stuff. I did a ramp test (Zwift protocol, using Kickr in erg mode) twice in a row (yes, yes, I know it's supposed to be a stand alone test) and then again three days later. Got the same result each time. Which just confirms my inability to push hard on a trainer (which I kinda knew anyway - I used to row and never could do a decent 2km on a Concept 2 erg) (but ergs don't float). It's a head thing I think.

Did a group indoor interval session literally a day after the third ramp test on a LeMond with P1's, and at the end my Garmin App suggested an increase in my FTP of 25% (based on what? Not sure - presumably it's something built in to the Garmin App?).

Thinking of just doing either the 20 minute thing or even one hour around the velodrome if I can cope with the boredom. Just to get another reading to confuse me further.

Hopefully by the time I get to race in the Southern Hemisphere summer, I'll have figured out what best works for me to get a reasonably accurate approximation of FTP, but I guess what I've really learnt is that I probably need to use the same kit each time (currently too many options - Kickr, P1, old powertap hub and LeMond Wattbox. I should probably just use calibrated P1's each time for consitancy), and find a protocol that does actually work for me...

Or stick with heart rate.