No it doesn’t use a best 20 minutes. It factors in a lot more. And also remember they (TR) are trying to get the best training measure for doing their plans, not getting the number closest to a lab test or anyone else’s test.
I think it’s safe to assume every bit kid power data is factored.
The question and secret is “how” it’s factored into their algorithm. Doubtful it’s 95% of your 20 minute power but doing sustained bouts of power is probably factored in somehow.
All the models that use “best” times for 5,20 or even an hour are flawed if you don’t do all out efforts.
My AiFTP was 301 last time I did it (I use 300 based off training and TTE work at threshold, I just do the AiFTP when curious) but intervals (which is an amazing product) has me at 283 eFTP. Because I haven’t done any max efforts in a while. Even doing 75 minutes uninterrupted at 90% doesn’t change their modeling.
I need to figure out how to do that but training peaks sent me a notification updating my FTP from 268 to 290. Again I’m not doubting TR AiFTP and it’ll be another 3 weeks before a detection is done again. I just found it interesting. Also if I manually set my TR FTP at 290 there’s no way I’d be able to complete the workout. Especially seated.
Apologies for any confusion. Per TrainingPeaks: * Power Threshold - Bike or Mountain Bike: We suggest a threshold increase if your 95% of your Average Peak 20 Min Power is greater than your currently set threshold.
Which Garmin do you have? And if a x30 or x40 model is it completely setup? FWIW I’ve got a Garmin 530, have it configured correctly, and it offers updates at least several times a month (usually more). These models use machine learning of power, HR, and HRV provided you have a compatible HRM.
TrainingPeaks is pretty simple. TP won’t update if your FTP is declining. As posted above it looks at 95% of 20-min power, and if it is greater than current FTP than you get a notice.
You can inspect your power curve and get a good idea what WKO and Strava will tell you, which in my experience is similar to what I get from Intervals.
If you want to test it for shits and giggles, create a workout with a 35min block at FTP, set your FTP to the garmin/TP # and try it out.
You have to REALLY skew outside the norm to have a TTE that is less than 30min, so a 35min test is perfect for calibrating FTP.
If your FTP is closer to 270 than 290 you will know in the first 10-12min if the wheels are going to come off. If you blow past 20min and start falling apart near 30 the higher number is likely correct.
For me, my FTP is a metric to determine my workout intensity. It really doesn’t mean anything beyond that. IMO I now have 3 FTP’s. One I can hold on the trainer. One I can hold seated, and one I can hold with a mixture of sitting and standing.
My TR FTP is still set to 268 and the intensity of my workouts right now feel just about right. Outdoors I can hold a little more power but I’ve still kept my zones in the old range. For example, Z2 feels good between 180-200w (based off 268 FTP). I’m not planning on doing my outdoor Z2 rides in the 200-220w range. At least not for now.
FTP and similar concepts (critical power, mlss) are about a small range of power that separates stable physiology from unstable physiology.
Unstable physiology is easy to feel and watch on your bike computer - increase in breathing from heavy rhythmic to ragged, and HR that keeps increasing.
If you can’t feel/see it you aren’t paying attention.
People tend to get wrapped up in debating the duration part - how long you can ride at it - and forget that it’s a narrow range of power that serves as a boundary between stable and unstable physiology.
Last week I listened to Cory Lockwood talk about setting the new USA 40km ITT record on Empirical Cycling podcast. At one point he does a good job of describing what it feels like to teeter back and forth across that boundary.
FTP really is that simple.
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