Question for the Ex.Phys Boffin(s) (AWC, Power-Duration)

rmur17

I'm finding it hard to get the proper wording here so apologies in advance!

I'm wondering about the contribution of anaerobic sources (loosely AWC) as one moves out along the power-duration curve.

Pretty clearly, for maximal (or close to maximal training efforts) in the short-end of the range, we're operating well above CP/FTP and drawing heavily upon anaerobic sources. CP-AWC analysis would indicate that.

But what happens when we get up to the following power-durations:

1. 10 MMP?
2. 15 MMP?
3. 20 MMP?
4. 30 MMP?
5. 60 MMP?
6. 120 MMP?
7. 240 MMP?

I won't bother going any further than that!

Once we move to the right along the P-D, do we or can we access much of those 'AWC' sources?

My own purely 'feel' take on things is that, when I work down around the 15-20 MMP range, I feel I'm accessing a sizeable portion of 'AWC'. At the e/o an effort I'm breathing heavily (high rate of Vo2) and the legs feel empty/drained/anaerobic.

However once I get out past 30-min or so, the sensations are much different near failure. At least indoors (where I figure I'm limited by cooling somewhat), I never feel that same 'drained/empty' feeling at the e/o of a very hard to maximal effort like I do on the short-end. Sure I feel like dog-doo the last few minutes and the legs are hurting etc but I don't breathe *that* heavily nor do the legs feel absolutely horrid. Failure seems truly 'multi-factorial' .

The same holds true as I go further and further out ... about 2-hrs indoors is about the limit that I've ever done for a MMP effort and it wasn't much fun the last 30-min or so but I never felt maxed out near the end in the same way I would during a 15-20 MMP effort.

Now I realize those are my PE/sensations ... but am wondering if it is reflective of the underlying processes or just my head ...

Sorry again if the question isn't framed very well. Feel free to answer the "real question" I'm trying to ask!

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rmur

frenchyge

Possibly this is just a clarification of the question rather than an answer, but I thought:

1) the CP model itself breaks down at longer durations, because there is no power level which can be held indefinitely.
2) AWC represents work which can be done over and above that supplied by *critical power,* and as such it doesn't mean that the necessary energy is being supplied by anaerobic sources. The extra ~3w that AWC represents over the course of an hour is certainly still coming from aerobic sources, as you mention.
3) I can still punch it up to 400w+ for 30-60 seconds at the end of a 2hr SST ride, so the anaerobic energy is still there for access, but the multi-factorial muscle fatigue generally protests it's use.

Markster

Why/how is the extra ~3W coming from 'aerobic' sources? I guess you meant 'anaerobic'?


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I would say that just means that you didn't try as hard as you could have during the 2hr effort, and hence still had some anaerobic capacity left to use in that 30-60secs.

acoggan

No, he meant aerobic: since critical power is below VO2max, you have to exceed critical power by more than a handful of watts before contribution from anaerobic energy sources is significant/required.

Urkiola2

Although I believe I understand what you say, with all due my respects, I believe that your statement is a bit confusing as well as probably not accurate.
If you talk about Anaerobic work capacity, then you cannot describe an aerobic metabolic state in your definition.
Determaning with such an accuracy, ~3w, that your source is aerobic seems to me extremely difficult...even to estimate it, especially when you talk about a course of an hour, which is done in the aerobic state, regardless of the intensity, unless, as you well say in your point 3 you sprint for 30-60 secs.

Cheers

acoggan

I think this is where distinguishing between anaerobic capacity as a physiological ability and anaerobic work capacity as a mathematical construct can be helpful. The latter is obviously meant to (and generally does) represent the former, but recognizing the fact that at their core they are really two different things helps explain such apparent discrepancies.

frenchyge

I'm not sure that the OP ever really got an answer to his question, but I think the recent discussion does highlight the difficulty in trying to directly relate the physiological phenomena with the mathematical modelling, especially at the longer durations where even the math gets a little tenuous.

rmur17

No I haven't. I'm just being patient ...

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rmur

Steve_B

You may be waiting a while for your answer. Take off your coat and stay a while.

amartinez

Rick, have you tried to fit Riegel's Endurance Equation to this data ?

rmur17

whoops sorry I missed your post! What exactly might that be?

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rmur

amartinez

A linear fit of Log(MMP) vs Log(Duration) in this range of duration, just curious how good would be the fit and the slope value.

Alex Simmons

I don't know about the data that was posted but for a bit of fun I decided to do my own chart. He is a picture of my MMP from 2005/06 and 2006/07:

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http://www.cyclecoach.com/

rmur17

thanks for posting Alex. Pretty darned good fit over two seasons of data. Now, other than a high y-intercept and shallow slope being good things, what does it tell us? Ale et al? i don't see a magic % from 'AWC' bar on there

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rmur