Strongly disagree with this. FTP and “TTE” are just plotting a point on your power curve.
When you say you strongly disagree, what exactly are you disagreeing with?
That TR couldn’t (or shouldn’t) give a TTE Detection/Prediction/Estimate along with their FTP Detection/Prediction/Estimate?
Your FTP would be a point on a power duration curve. TTE would be the y coordinate for the x coordinate of your power at that duration.
TR could model that curve more precisely with more data, and by extension get a more accurate “TTE”, but that’s still describing a curve, not two separate things called FTP and TTE.
Other way round, as it’s usually plotted. Power on the y axis. Time (or more usually log of time) on the x axis.
I’m still not sure what you’re disagreeing with. I think @GoLongThenGoHome identifies a valid point in that experience tells us that increases in FTP are often accompanied by a decrease in TTE. That’s why after an FTP bump, TR resets your Threshold workouts back down to lower PLs, and why a coach would often follow an FTP increase with extensive threshold work to bulld TTE back out.
I just don’t see why you’d introduce another metric (a point on a power curve) instead of showing users that power curve -actual or estimated- and letting them see their “TTE” at any point on the curve.
You’re suggesting that TTE - for example at FTP - can’t be trained independently of that FTP?
I’m suggesting that TTE isn’t separate from FTP. FTP is a combo of duration (TTE) and a given power. You could train to go longer at that power, but your power curve would necessarily change.
If you could do 250w for 40 minutes, then you trained and you could do 250w for 50 minutes, you would also now be able to go more than 250w for 40 minutes, otherwise you’d have a flat spot from 40m to 50m on your power curve, which would break the CP model.
Yes.
Maybe that suggests the model is flawed..
Fair, but that’s a separate argument. Are you saying -setting the CP model aside- that you can imagine physiology where MMP power doesn’t decrease as effort duration increases?
This is a fair argument, but there is a massive contingent that doesn’t want to test to figure out what their FTP is, and loves having an AI FTP to keep them from testing. Knowing this, that same contingent isn’t going to settle for “you pick the duration you want to call FTP and then check what your current spot at that duration is and call it your FTP”. I prefer to do the Kolie Moore test for exactly this reason, but I think you’d have a massive rebellion if you told everyone they have to test to get their number.
We have the same issue with, say, 10 minute power, on the curve. I can go do 30/30s for 10 minutes and get a max number on my power curve that is going to either be higher or lower than my “steady max effort” 10 minutes number is. This was a big problem for me when using TR. It would tell me an interval fell below my power curve, so I should be at Moderate FTP, but my power curve was set from a totally different kind of interval, so the workout felt Very Hard, not Moderate, for example.
If be questioning the method to determine ftp if tte is regularly going down with an increase in ftp. Then you’d need to think how’d much tte would vary just by sampling error when ftp does not change.
Well, another 4 weeks have gone by, and this time it was a 1-watt increase to 349 but not after a confusing last week.
The last interval ride, 8 days out from my next ftp detection, I did a VO2 5.9 workout. I messed up one of the intervals and ran out of downhill, so I had to stop pedaling for a few seconds. Otherwise, numbers were fine. The prediction went from 355 down to 348. This was after mostly floating in the 360s for most of this block.
Then onto a rest week. I was on a family trip and had to shorten 2 rides by 30 mins, which by the time I did this was a -3 watts for my FTP detection. On Friday, I went from James to Pioneer -3 based on only having 1 hour available. However, after I completed the ride, my prediction jumped up to 349.
Overall I’m not complaining because I did think 348 was a good number and the workouts have started to lean tougher. I was frustrated that picking shorter rides during a rest week could cause a 3 watt drop.