eFTP and out of saddle

1

Hi All,
Just curious, to my understanding, FTP should be based on in saddle riding only, I think… How does intervals.icu eFTP know when is a rider out of saddle? I use TrainerRoad and that’s fairly straight forward as all my rides I do in saddle so their AI FTP estimation should be fairly in the ball park but what about intervals.icu?

2

The assumption is that you’re sitting for an FTP test. I’ve never read or heard about any FTP test or model being based on a person standing.

You might be able to boost your FTP test result by standing, especially for a shorter version test, but is that higher FTP going to help you in your training when you can’t complete your workouts? In the end, that FTP number only matters to you.

3

I am not referring to any specific FTP test as that, I always do sitting. I am referring to interval.icu’s eFTP which I assume they take a lot of ride data and get an estimation. The question is if the data they collect from rides will end up with rides that are out of saddle and this can skew the eFTP result to be possibly higher than actual?

4

You need to understand what Intervals is doing to estimate FTP:

  • When a power interval is detected with a higher Power value then included in your PDC curve, for a duration equal or higher then what is set on the settings page, Intervals considers this a breakthrough and returns a new eFTP value. It is NOT based on a mix of rides… And there is no calculation going on based on Power/Duration from that interval.
  • The power value for that duration is matched to a known power curve from a database made by FastFitness Tips, and the eFTP returned by Intervals is the FTP that would result from that curve. Basically, your result is compared to the results of a large number of other riders with a known PDC curve.

It is important to set the minimum duration for the considered intervals correct for your profile. If you know you have a higher then average Anaerobic capacity, set the minimum length to at least 5min. That will avoid an over-estimated FTP in that case.

1 Like
5

It’s a model (formula) estimation. You can see which model is being used. It doesn’t know if you’re standing or sitting. It’s looking at points along your PDC, same as WKO, TP, Zwift’s new racing category system, and probably to some extent TRs AI FTP.

In the end, it’s an estimate which is only as good as the inputs (PDC). Hence, proper care and feeding of the PDC is necessary. And yes, standing can affect power especially for short periods.

2 Likes
6

Ok, thanks. I think I get it…
I have my min duration set at default of 180 seconds.
Regardless, I do very little out of saddle riding anyways.

7

You should probably change that to 300 seconds. That was the old default which is a bit short.

1 Like
8

HaHa. ‘Feed the model’. Where have we heard that before?

1 Like
9

FYI…my model is very malnourished currently :sweat_smile:

1 Like