Quick question about Normalised Power and F. threshold power

springtide9

Alex_Simmons/RST wrote:

springtide9 wrote:

The question is whether this statement holds true for other types rides, specifically where intervals are involved.

Yes it does. Indeed pre calculating the Normalised Power for an intended interval workout of about an hour's duration is a good way to establish whether or not such a workout is indeed feasible to begin with.

If you are seeing a reported IF of ~ 1.1 from about an hour's worth of training, then at least one of these three things has occurred:
- the power data is incorrect (e.g. torque zero not properly set, or slope calibration not correct);
- normalised power has been incorrectly calculated (e.g. smart recording is in use, or using software that doesn't correctly calculate it);
- your FTP is higher than you think it is (assuming above two don't apply, then will almost certainly be the case).

Thanks for the reply and information.

I am pretty sure the PT is fine as I usually do the recalibration before every ride as well as having the smart recording as off, "including power" zeros etc
I have used two different PT's due to the wheel doing out of true multiple times (seems common on the new PT Pro rear wheels), but both give similar data.
TP is also calculating the TSS/IF data, as the values are slightly different to the Garmin data; enough to know they are not being rounded up/down, but not enough that it changes the overall impression.
Due to a lack of being able to do a proper Threshold test, I've been using Golden Cheetah to calculate my CP, which although not ideal, was better than nothing.

I just uploaded my next batch of data from this week and its now shifted my CP to 324 (from 306)... the shift seems to be down to two data points in one of my training rides, 10 mins @ 370 watts and 15 min at around 350 watts. Obviously these are not proper intervals, just sections pulled from a ride:
http://flickr.com/gp/peppernet/F6Nn24

I have set my CP to 324 for the time being until I get around to doing a proper 20 min test. I guess I'll just have to wait and see how the performance manager data looks in about a week or so's time.

I really should sit down and try and work out a more structured training plan. I have bought a few books so will see if I can make sense of them again, it's just that I do glaze over at some of the training as the entire plan seems very clinical in terms of racing for best performance, where as I really want something in-between.
I also seem to be improving better than I expected without any proper structured training for my age (43), and almost feel I should be putting my efforts into weight loss (86kg)

Anyway, thanks for your help. If I do decide to bite the bullet and get a proper training plan or coaching, RST will obviously be my first port of call :-)

amaferanga

springtide9 wrote:

Due to a lack of being able to do a proper Threshold test, I've been using Golden Cheetah to calculate my CP, which although not ideal, was better than nothing.

That's your problem. Unless you have done proper all out efforts for suitable durations then this number is unlikely to be very close to your FTP.

If you can do 350W for 15min as part of a ride you can almost certainly do >350W for 20min in a well rested all-out effort. 324W is probably still an underestimate, but definitely closer than 306W.

neeb

OP back again...

So I got the powertap setup on the indoor trainer and it is MUCH easier to keep a constant power output and get AP and NP to be effectively the same (a bit of a relief as I was starting to wonder if the power meter was faulty the way it jumps around on the road, but I guess it's just the total lack of completely flat roads where I am).

Did a 20min maximum effort test the other day to estimate FTP. Pretty sure it was as maximum as possible... Took 95% of that AP as my FTP (incidentally, that value was 5w less than the NP value I got on the road with the very variable 1 hour effort). Tried to do 2x20 today based on that FTP. Problem is I couldn't finish it, managed the first 20mins at around 101% of the estimated FTP, but then blew up 5mins into the second 20mins... (5 minutes easy pedalling in-between)

So I assume (almost by definition) I am still slightly overestimating FTP? Or could be something to do with the FTP test being done on a tacx "real life video" climb with some gradient variability, while the 2x20 was done on tacx catalyst at a constant resistance? (all power readings from the powertap of course)

Alex_Simmons/RST

See Sin of Sins #6
http://alex-cycle.blogspot.com.au/2009/ ... ftp-2.html

ChrisSA

Or you could just be tired from the first 20min effort the other day?

How did you do the 20min max effort - what was the warmup etc? Personally I think a 2 x 20minute should be done in the sweetspot rather than FTP. FTP should be shorter intervals of greater frequency.

neeb

Alex_Simmons/RST wrote:

See Sin of Sins #6
http://alex-cycle.blogspot.com.au/2009/ ... ftp-2.html

Interesting - I may indeed be sinning...

ChrisSA wrote:

Or you could just be tired from the first 20min effort the other day?

That's also possible, as is being negatively affected by (unusually for me) having two or three beers yesterday, although the session was nearly 24 hours later and I felt fine.

ChrisSA wrote:

How did you do the 20min max effort - what was the warmup etc? Personally I think a 2 x 20minute should be done in the sweetspot rather than FTP. FTP should be shorter intervals of greater frequency.

Warmup was just 10mins of around 50% of FTP with two or three short sprints to open the legs up, not the whole caboodle as recommended in the TaRWaPM book.

In any case, I'll try the next session about 4% lower - it'll either be nearer FTP or nearer "sweetspot"...

neeb

Another explanation could be the gearing - the constant resistance level I had chosen had me feeling I was right between two gears so that I couldn't quite hit a cadence that felt perfect.

SBezza

Remember the 2x20 don't have to be done at FTP, going near it say 95% will still result in gains. If you feel the ideal cadence is between gears, and I know what you mean here, try and up the resistance of the turbo if you can to bring it closer.

neeb

SBezza wrote:

Remember the 2x20 don't have to be done at FTP, going near it say 95% will still result in gains. If you feel the ideal cadence is between gears, and I know what you mean here, try and up the resistance of the turbo if you can to bring it closer.

Yes, I was going to do that. I'm using the slope/time option in the tacx software (I have the fortius trainer), if I set the slope to a different value I'll get a different resistance. I had the slope set so that a cadence of 95ish was using fairly large sprockets and the gaps between them are bigger at that end of the cassette.

However, I also can't help feeling that I was able to put out more power during the max effort test because I was using the tacx "real life video", which provides a pretty realistic climbing experience with constant slight variations in gradient. It was a route I was very accustomed to, so I easily settle into a rhythm and go slightly harder in some parts than others. There's also something about the simulated climbing experience with the video footage that makes you treat it more like a real climb with more out-of-the-saddle efforts etc, even although ultimately you are just pedaling against the same roller resistance that you can set in the "catalyst" training application.

The great thing is that now I have the powertap I can actually quantify/confirm these apparent differences. It may be that it would be beneficial for me to train more with a constant resistance and try to get my average power values up to the same level I can sustain in the simulated climbs.

neeb

OK, I managed a 2x20 today at 99% and 98% of the same calculated FTP. It felt very hard but not "extreme". (The 20mins 105% test felt "extreme").

So I think I must be in the right ballpark. I attribute the failure the other day to a combination of factors - 1) There's a surprisingly big difference between 99% and 101%. 2) I think I started too hard at the beginning 3) Tiredness / off-day.

Does that sound plausible, or should I maybe knock another 2 or 3 % off my assumed FTP?

Alex_Simmons/RST

4) you gained some fitness (even one good bout can give a small boost)

These are self regulating. When they seem easy (relatively), then bump up the power. If you don't get through them, then drop it down. You do this not only from session to session, but depending on how you feel during the session.

Depends also on how often you do them. Weekly only, then what you describe is about right. 2 or 3 times / week, then you'll want to drop it a little more.

neeb

Thanks, makes sense.

Alex_Simmons/RST wrote:

Weekly only, then what you describe is about right. 2 or 3 times / week, then you'll want to drop it a little more.

If your sole objective was to increase FTP, would it be better to do several lower intensity 2x20 sessions (say, 90-95% FTP) or one high intensity one mixed with other types of training?

Alex_Simmons/RST

neeb wrote:

Thanks, makes sense.

Alex_Simmons/RST wrote:

Weekly only, then what you describe is about right. 2 or 3 times / week, then you'll want to drop it a little more.

If your sole objective was to increase FTP, would it be better to do several lower intensity 2x20 sessions (say, 90-95% FTP) or one high intensity one mixed with other types of training?

Yes.