Originally Posted by
NoWhammies
So. My Garmin has the 'auto FTP calculations' feature enabled. Back in June I sent out and did a very hard/fast ride. At the end of the ride, my Garmin said "Congratulations! You set a new FTP record. Do you accept?". And yes, this was in fact a new FTP record for me because I knew what my old FTP was. So I clicked yes.
A few weeks later I was out for a ride. A fast ride, but nothing like the ride back in June. At the end of the ride my Garmin said "Congratulations! You set a new FTP record. Do you accept?" Now, this FTP was definitely slower than the one from June. So I clicked no. I then went in an doubled checked my Garmin FTP setting. It was the higher setting from June.
A month or so after that I was out on a fast ride and again. At the end of the ride my Garmin said "Congratulations! You set a new FTP record. Do you accept?" This FTP was again lower than the June FTP. But what the heck, I said yes and went on with my day.
This has happened a few times since. Sometimes the FTP is higher than what is recorded, other times lower.
Anyone have any idea what's going on here? The only thing I can come up with is the FTP calculation involves weight, correct? And I use my Garmin scale daily. So is Garmin calculating a new FTP for me each time based on my weight? Thank you.
I don’t use and cannot speak to the Garmin software, but I have been doing power-based training with a cycling coach for 11 years and have some thoughts which may be helpful to you.
First, I would not be concerned with the Garmin FTP estimates every few weeks. If you were on a training regimen, you’d need to give the training time to work so a new estimate based on non-specific activities every few weeks doesn’t matter, and if you’re not on a training regimen, what does a bi-weekly FTP estimate matter? You’ve already indicated that you’re aware of perceived exertion and so it doesn’t sound like you’re metering your efforts based on FTP either.
FTP outside of a training plan just doesn’t mean much, and if it’s estimated based on efforts which are not specifically performed to evaluate maximum power output (for an hour, i.e FTP) then it means even less.
I’d suppose it’s nice that Garmin asks if you want to accept new estimates because the machine cannot otherwise know if you made a specific maximum effort to evaluate FTP. I would not accept a new estimate unless I had.
I also would not concern myself with a new FTP estimate unless I was consistently riding well beyond my numbers to the point the zones were irrelevant or I was doing a structured training regimen which I wanted to evaluate the results of.
None of that is to say there’s only one right way to ise FTP, but the number can be misused, assumed to mean things it does not. For example, a lower FTP estimate from Garmin than what it estimated two weeks prior does not mean you should change your behavior…especially if you did not specifically perform an effort to evaluate FTP and/or you’re not on a training program to increase FTP.
Yes, Garmin is offering tools to make training easier, and I’ve no doubt they are helpful when used properly in the course of training. I’m not aware of any training program which requires FTP assessment every couple-or-three weeks, nor every fast/hard ride. Garmin provide the service, but it’s incumbent on the rider to use it properly.
In short, ignore the FTP estimates except in cases where you’re riding to evaluate FTP.