1st time long TT to determine FT Power

[sugaken]

Hiya,

I'm new to the world of training with power, in fact I got my PowerTap SL only a couple of months ago.

I have some idea where my FT power is around, but let's say I don't really know my true FT power (which is true) and I am about to do a long TT (~1hr) to find out, which I can do only every so often because I cannot find any suitable course where I live and I have to travel far to do that.

Obviously it would be best to start out and maintain the same level of output (at FT power, obviously ) throughout the TT session, but it would be difficult to do that if you don't already know your FT power.

So, what's the best pacing strategy in such a situation where you want to maintain a level of output as constant as possible, yet as high as possible, for a longer period of time than you can routinely reproduce in your daily training sessions?

For the purpose of determining FT power, would it be ok to start out at a higher power output which you might not be able to sustain for the entire duration of the session, later taper off to and settle into a somewhat lower, sustainable level of power output, then take the average power over the entire TT session as your FT power?

I have tentatively set my FT power to 220W when I started using my PowerTap, but I'm starting to suspect that it might actually be a little higher than that now, up to ~240W or so.

TIA, and I apologize if it's a FAQ.

 

[sugaken]

Geez, I feel stupid already... the answer was in front of me staring at me right in my face...

http://www.cyclingpeakssoftware.com/threshold.html

4. Since by definition the best measure of performance is performance itself, the most direct estimate of your sustainable (threshold) power will be obtained by simply doing a ~1 hour TT. By examining the horizontal graph of the data from such a TT in CyclingPeaks Software (perhaps with a little smoothing applied), you will be able to quickly tell whether your effort was well-paced, or if perhaps you started out too hard and then later faded, resulting in the average power somewhat underestimating your true threshold power.

I had the browser window open all while I was writing my original post... duh.

However, having read the paragraph above, this question occurred to me:
If "you started out too hard and then later faded", would Normalized Power better indicate your true FT power than Average Power?

 

[RapDaddyo]

If "you started out too hard and then later faded", would Normalized Power better indicate your true FT power than Average Power?

Yes. Actually, you can get a pretty good approximation of your FT by doing a shorter, max power test and then applying a typical MP/duration curve. Let's say you do a 5-min max power test. Take your 5-min AP and divide by 1.2 and that'll get you in the ballpark. Or, do a MAP test on a trainer and your FT will likely be in the vicinty of 75%MAP. Or, you could do ~3 MP tests (e.g., 3, 6, 15 mins) and use the Critical Power Model to estimate 60min MP. Lots of ways to estimate what it will be so as to start your test as close as possible to the right number.

 

[sugaken]

Thanks, RapDaddyo.

Yeah, I've read Ric Stern's power zoning article at cyclingnews.com and I figure my MAP is ~320W from the bicycle ergometer wattage readings during VO2max I took last October. However, I didn't quite feel that I could ride at 72-77%MAP (230-246W) for an hour.

But in recent 20min x2 intervals I scored 250W for the first set and 229W for the second, average of which is coincidentally ~240W, so maybe I should've just used 240W calculated from my MAP in the first place...

At least my plan is, when I get to do the longer TT, I'll start with 240W to see if I can maintain it for an hour.

 

[kenji]

Konbanwa, sugaken!

As RapDaddyo says, you may want to do 5MP tests. However, be careful about the ratio between 5MP and FTP. It varies by person, widely.

This is an example of 5MP = 107%FTP :
http://www.cyclingpeakssoftware.com/powerprofile-tter_v4.xls
And this is an example of 5MP = 122%FTP :
http://www.cyclingpeakssoftware.com/powerprofile-pursuiter_v4.xls

If you have relatively high anaerobic capacity (I think it may makes 5MP higher) then you might overestimate your FTP, and vice versa. It's safe to start with lower-edge of the estimation, IMO.

But in recent 20min x2 intervals I scored 250W for the first set and 229W for the second, average of which is coincidentally ~240W, so maybe I should've just used 240W calculated from my MAP in the first place...

You started out too hard .
In addition, you may want to do 2x20s with 91~95% of your (estimated) FTP so that you can spend more time in Coggan's L4. IMO it is more effective to grow your FTP ( at least worked for me ).

 

[mattv2099]

Let's say you do a 5-min max power test. Take your 5-min AP and divide by 1.2 and that'll get you in the ballpark. Or, do a MAP test on a

Wow, That algorithm puts me less than 1% off of my FT determined by my 20 minute power.

I'm a fan of the 20 minute power test. Ride as hard as you can for 20 minutes. Multiply the average power by .95 and use the result as your FT.

Buy the book "racing and training with a power meter."

 

[frenchyge]

For the purpose of determining FT power, would it be ok to start out at a higher power output which you might not be able to sustain for the entire duration of the session, later taper off to and settle into a somewhat lower, sustainable level of power output, then take the average power over the entire TT session as your FT power?

I'd be afraid that starting too high would make me frustrated and want to quit the test in the middle. Personally, I would start ~5% below target (240w, in your case) for the first 20-min, pick it up to the target value (if possible) on the next 20-min, and dig as deep as possible on the last 20-min of the test. Well, that's if I were really determined to do a 1-hr TT to determine FT, rather than using one of the several other methods to estimate it.

 

[sugaken]

Thanks, everyone.

Personally, I would start ~5% below target (240w, in your case) for the first 20-min, pick it up to the target value (if possible) on the next 20-min, and dig as deep as possible on the last 20-min of the test.

That sounds good to me. I'll try that. Thanks.

Well, that's if I were really determined to do a 1-hr TT to determine FT, rather than using one of the several other methods to estimate it.

Well, I would probably rely on other, easy-to-repeat, estimation methods when I have more experience with training with power so I have a pretty good idea how those ballpark figures would translate to my real FT power.

But as I said earlier, I just got started with this "training with power" thing, and I really think it will make me feel better if I do a 1hr TT, even if only to get some idea how my previously tested power figures match up with my 1hr TT power.

Yeah, I guess I am determined to determin FT by doing a 1hr TT.

 

[Spunout]

You could do a 20 minute TT as a proxy, and use your own personal factor (compared to your 1 hour test) to adjust it. That way, when you want to do a test on a rest week it is a simple 20 minute TT.

 

[frenchyge]

Well, I would probably rely on other, easy-to-repeat, estimation methods when I have more experience with training with power so I have a pretty good idea how those ballpark figures would translate to my real FT power.

But as I said earlier, I just got started with this "training with power" thing, and I really think it will make me feel better if I do a 1hr TT, even if only to get some idea how my previously tested power figures match up with my 1hr TT power.

Yeah, I guess I am determined to determin FT by doing a 1hr TT.

No problems there. I did the same thing when I first got my power meter. Unfortunately, I got frustrated by how hard the 1-hr TT effort was, and quit. After that, I convinced myself that the 'easier' methods were just as good, and never looked back...

 

[sugaken]

Unfortunately, I got frustrated by how hard the 1-hr TT effort was, and quit. After that, I convinced myself that the 'easier' methods were just as good, and never looked back...

Duly noted. But the races I target are >1hr hill-climb races (with minimal drafting effect essentially ITTs), so I hope I won't start wanting to quit in the middle...