Why is my 1-hour NP lower than predicted?

1) It wasn't as hard as you thought

2) You sat in and coasted during the ride, increasing time at 0 watts.

Spunout said:

1) It wasn't as hard as you thought

Maybe. It felt quite hard though... :o

Spunout said:

2) You sat in and coasted during the ride, increasing time at 0 watts.

True. I did quite a bit of coasting, so it's not surprising that my average power was low. What surprised me was that my NP was not higher, but maybe there was too much coasting for the NP algorithm to work properly?

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CycleFast

Spunout said:

1) It wasn't as hard as you thought

2) You sat in and coasted during the ride, increasing time at 0 watts.

#2 can be ruled out, since we're talking about normalized power here. There are other possibilities, however:

3) Your anaerobic capacity is significantly higher than average, such that taking 95% of your 20 min power overestimates your functional threshold power.

4) You weren't as fresh for the race as you were for the formal 20 min test.

5) You're looking at the peak 60 min average power for the race, not the peak 60 min normalized power.

6) Your powermeter wasn't zeroed properly on one of the two days.

acoggan said:

#2 can be ruled out, since we're talking about normalized power here.

OK, good, then I've understood the NP concept correctly.

acoggan said:

3) Your anaerobic capacity is significantly higher than average, such that taking 95% of your 20 min power overestimates your functional threshold power.

Wow! I thought it would have to be the other way around. I'm was thinking that if I really had a high anaerobic capacity that would result in a high NP in a race like this (which it did not), because it would allow me to repeat hard efforts a lot of times, while a poor anaerobic capacity would make me perform relatively better at aerobic efforts (like the 20min TT).

acoggan said:

4) You weren't as fresh for the race as you were for the formal 20 min test.

That might be.

acoggan said:

5) You're looking at the peak 60 min average power for the race, not the peak 60 min normalized power.

True, but how do I find peak 60min NP?

6) Your powermeter wasn't zeroed properly on one of the two days.[/QUOTE]I think it was, it showed 0W while coasting on both days.

Thanks for your contributions.

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CycleFast

CycleFast said:

I thought it would have to be the other way around. I'm was thinking that if I really had a high anaerobic capacity that would result in a high NP in a race like this (which it did not), because it would allow me to repeat hard efforts a lot of times, while a poor anaerobic capacity would make me perform relatively better at aerobic efforts (like the 20min TT).

The ability to repeatedly raise your effort to a very high level is a function of your aerobic/metabolic fitness, as indicated by your functional threshold power. That is, the more fit you are, the quicker you will recover from each such effort, such that you can go hard again. A higher-than-average anaerobic capacity will allow you sustain a power in excess of functional threshold power for a longer-than-average period of time, but once your anaerobic capacity is exhausted, you have to slow down to a sub-threshold pace to recover it. So, having a high anaerobic capacity relative to your functional threshold power would be helpful in a 20 min TT, but doesn't necessarily help you crank out a high normalized power for ~1 h.

CycleFast said:

how do I find peak 60min NP?

Given the duration of the race, I don't think this is the answer, but thought I'd mention it anyway just to cover all the possibilities. Anyway, the easiest way to find your highest 60 min normalized power would be to clone the mean maximal power curve for that race, then reset the channel to normalized power. You can then move the cursor along the curve until you get out to 60 min, and read off the value in the pop-up box.

CycleFast said:

it showed 0W while coasting on both days.

Again, just covering all the bases.

BTW, here's another one:

7) the neuromuscular demands of the race were so different from your usual training/what you're body "likes" to do that you weren't limited by your metabolic fitness (functional threshold power), but by other factors. Performing a quadrant analysis of the race file:

http://home.earthlink.net/~acoggan/quadrantanalysis/

therefore might provide some additional insight.

The NP/AP ratio (1.16) supports your perception of a lot of surges and accelerations. The question is just how many surges were anaerobic and what was the cumulative anaerobic effort after the 1st hour? I think this would help you include or exclude your AWC as the prime cause of getting dropped after 1 hour.

As Andy said, a high AWC could skew your FT estimate using the 0.95 formula, but that would be a huge difference (0.85) and I think very unlikely (although I don't have access to the amount of data Andy does, so I'm just making a logical extrapolation).

acoggan said:

The ability to repeatedly raise your effort to a very high level is a function of your aerobic/metabolic fitness, as indicated by your functional threshold power. That is, the more fit you are, the quicker you will recover from each such effort, such that you can go hard again. A higher-than-average anaerobic capacity will allow you sustain a power in excess of functional threshold power for a longer-than-average period of time, but once your anaerobic capacity is exhausted, you have to slow down to a sub-threshold pace to recover it. So, having a high anaerobic capacity relative to your functional threshold power would be helpful in a 20 min TT, but doesn't necessarily help you crank out a high normalized power for ~1 h.

Aha! 🙄

acoggan said:

Anyway, the easiest way to find your highest 60 min normalized power would be to clone the mean maximal power curve for that race, then reset the channel to normalized power. You can then move the cursor along the curve until you get out to 60 min, and read off the value in the pop-up box.

Aha! 🙂

acoggan said:

7) the neuromuscular demands of the race were so different from your usual training/what you're body "likes" to do that you weren't limited by your metabolic fitness (functional threshold power), but by other factors. Performing a quadrant analysis of the race file:

home.earthlink.netquadrantanalysisOpen ↗

therefore might provide some additional insight.

Good point. Is there any way I can do a quadrant analysis myself on my own data? I could probably construct a spreadsheet or something based on the formulas found in the articles, but has someone already made such a spreadsheet (or similar application)?
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CycleFast

CycleFast said:

Is there any way I can do a quadrant analysis myself on my own data? I could probably construct a spreadsheet or something based on the formulas found in the articles, but has someone already made such a spreadsheet (or similar application)?

If you go here:

http://www.cyclingpeakssoftware.com/power411.html

and scroll down to info on quadrant analysis, you can download some Excel templates that James Huntington put together and has kindly shared w/ the world.

RapDaddyo said:

As Andy said, a high AWC could skew your FT estimate using the 0.95 formula, but that would be a huge difference (0.85) and I think very unlikely (although I don't have access to the amount of data Andy does, so I'm just making a logical extrapolation).

I agree, very unlikely...in fact, the lowest ratio of functional threshold power to 20 min power that I've ever seen is still >0.9. Even so, I thought I should mention the possibility, just to make people aware of the issue. (Keep in mind as well that the accuracy of the normalized power algorithm is only about +/-5%, so the difference that CycleFast observed could due to "slop" in both numbers.)

[quote="acoggan"]the easiest way to find your highest 60 min normalized power would be to clone the mean maximal power curve for that race, then reset the channel to normalized power. You can then move the cursor along the curve until you get out to 60 min, and read off the value in the pop-up box.

[QUOTE]

I actually have a graph set up on my athlete homepage that gives me the mean maximal 60m AP, 60m NP, and 30mAP/NP for each day I ride, similar to the 5s,1m,5m,60m graph that's in the default setup. I find it pretty interesting.

beerco said:

I actually have a graph set up on my athlete homepage that gives me the mean maximal 60m AP, 60m NP, and 30mAP/NP for each day I ride, similar to the 5s,1m,5m,60m graph that's in the default setup. I find it pretty interesting.

Yeah, that's another way, and I'm glad that you brought it up, because many people seem to fail to realize that you're not locked into using just the four default durations. You can, in fact, define as many as you'd ever want (I'd say "an infinite number", but I'm not sure if that's true). Moreover, if the chart becomes too crowded to be legible, you can always clone it and set one up for shorter durations (to reflect neuromuscular power and anaerobic capacity) and another for longer durations (to reflect LT and VO2max). (A really good idea that I cribbed from Alex Simmons! 😄)

acoggan said:

I agree, very unlikely...in fact, the lowest ratio of functional threshold power to 20 min power that I've ever seen is still >0.9. Even so, I thought I should mention the possibility, just to make people aware of the issue. (Keep in mind as well that the accuracy of the normalized power algorithm is only about +/-5%, so the difference that CycleFast observed could due to "slop" in both numbers.)

just browsing thru the discussion .. and the >0.9 FTP to 20MP ratio caught my eye.

FYI/E, Kraig Willet claimed to have a repeatable ratio of ~0.85 FTP (60MP) to 20MP using average power only of course 😉 I can't recall the exact numbers ...

rmur

acoggan said:

If you go here:

cyclingpeakssoftware.compower411.htmlOpen ↗

and scroll down to info on quadrant analysis, you can download some Excel templates that James Huntington put together and has kindly shared w/ the world.

Great stuff, I can actually make my own quadrant analysis!

Thanks! 🙂

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CycleFast

acoggan said:

Moreover, if the chart becomes too crowded to be legible, you can always clone it and set one up for shorter durations (to reflect neuromuscular power and anaerobic capacity) and another for longer durations (to reflect LT and VO2max). (A really good idea that I cribbed from Alex Simmons! 😄)

Well the ideas ledger is firmly in your favour!

FWIW - Attached is a sample of what it looks like.... Charts are not too crowded for a season's worth of data and all you do is roll the pointer over any of the buildings and it gives you the stats for that block. In this case I chose to group data in 4 week blocks (since that is a common training programme meso cycle), but CP users can use whatever frequency they like.

Next to each of these I also have the same chart cloned but with watts/kg rather than just watts, to take into account weight changes through the season. Useful for tracking power profile changes.

Just remember that the final group of "buildings" on the right is for the current (usually incomplete) 4-week block.

As you can see I made OK progress with aerobic and neuromuscular power but my anaerobic progress was poor. That's what makes this so helpful, I can readily see what impact my training is having, weigh that up against the demands of my target events and adjust accordingly.

rmur17 said:

FYI/E, Kraig Willet claimed to have a repeatable ratio of ~0.85 FTP (60MP) to 20MP using average power only of course

Considering where Kraig lives (i.e., in a highly urbanized area with limited access to either uninterrupted flat roads or really long climbs) and how little he actually rides, I can believe that his best 60 min average power is only ~85% of his best 20 min average power. As you alluded to (with the 😉 ), though, that's not the same as saying that his functional threshold power is only 85% of his best 20 min power - to establish that, he need to get his butt out to Fiesta Island a couple of times, to do both the 20 km and 40 km TTs they hold there.

acoggan said:

Considering where Kraig lives (i.e., in a highly urbanized area with limited access to either uninterrupted flat roads or really long climbs) and how little he actually rides, I can believe that his best 60 min average power is only ~85% of his best 20 min average power. As you alluded to (with the 😉 ), though, that's not the same as saying that his functional threshold power is only 85% of his best 20 min power - to establish that, he need to get his butt out to Fiesta Island a couple of times, to do both the 20 km and 40 km TTs they hold there.

we started to get into a discussion about whether the corollary to "the more you do - the more you can do" (^TM AC) was "the less you do - the less you can do (^TM pending) 😉

I believe the efforts quoted were for a 20min hillclimb and 40k TT --- which of course brings climbing aptitude, drop in power due to aero position etc.... into the equation.

I used to be a 1.08 (or .92 ) bloke but it seems by 'doing more' - my ratio is normalizing to around 1.05 (or 0.95) now.