So what value should I use (the program choice is 300W, 320W, 340W) (based on 20min power, not 1 h power).

Cheers

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So what value should I use (the program choice is 300W, 320W, 340W) (based on 20min power, not 1 h power).

Cheers

Initially I was thinking of using 320W, but based on your race NP, I would be tempted to go wtih 340W. Races are always a good way to establish your power at threshold because you will probably be pushing harder in a race than you would in a solo 20 min TT test. It appears that your 20 min NP increased from a few weeks ago, so maybe 340W would be a better threshold value to use just based on the information in this thread so far.Blackie said:

So what value should I use (the program choice is 300W, 320W, 340W) (based on 20min power, not 1 h power).

Cheers

NM87710 said:

Blackie said:

So what value should I use (the program choice is 300W, 320W, 340W) (based on 20min power, not 1 h power).

Cheers

I'd use 300w at the most, but I'd bet it's closer to 280. I've seen 1 hr NP's of 30-50w higher than my threshold on rare occasions, certain courses will mess with the formula. If you consistently see 1 hr NP's from a variety of situations over 300w, then maybe you should adjust your threshold, but I certainly wouldn't do so based on 20' NP.

If you find yourself too fatigued to follow the plan using 340w as the number, you can always drop it to 320 or 300, right?

--Steve

Blackie said:

So what value should I use (the program choice is 300W, 320W, 340W) (based on 20min power, not 1 h power).

Cheers

The normalized power algorithm is pretty good, but tends to overestimate actual sustainable power during shorter efforts in which anaerobic capacity can play a significant role. That likely explains the 5-12% overestimation you seem to have observed. Given your apparent decision to use 20 min power as the metric by which you judge your metabolic fitness (which I definitely do

And the problem is compounded if the anaerobic efforts are on/off, because AWC partially recovers following each anaerobic effort. As Andy suggests, I don't use NP in performance tests unless the duration is at least ~30 minutes. I would especially not use NP is the NP/AP ratio was greater than ~1.03.acoggan said:The normalized power algorithm is pretty good, but tends to overestimate actual sustainable power during shorter efforts in which anaerobic capacity can play a significant role. That likely explains the 5-12% overestimation you seem to have observed. Given your apparent decision to use 20 min power as the metric by which you judge your metabolic fitness (which I definitely donotrecommend), you should rely on the average power, not the normalized power.

RapDaddyo said:I would especially not use NP is the NP/AP ratio was greater than ~1.03.

IMHO that's being a bit

Perhaps so. It probably reflects my newfound performance testing course. I only recently discovered that I have the perfect test course 1.6 miles from my house. This is an 11 mile straight road with a 1.6% steady grade into a prevailing 10-15mph headwind. After the climb, there is a 0.6% downgrade for another 9 miles. The prevailing headwind offsets the downgrade so it's easy to maintain power on this segment as well. I now use this course for all performance tests up to 1 hour and my NP is usually within 2W of my AP. I find that other courses that are much more variable grade can result in higher NPs than I typically do with rock steady power management, which I attribute primarily to AWC and AWC recovery. So, I'm probably just defining my criteria based on my newfound test track.acoggan said:IMHO that's being a bittooconservative. Normalized power from a maximal ~1 h effort is usually w/in ~5% of somebody's functional threshold power, even if the raw data are considerably more variable than what would be acceptable under the above criteria. If for some reason +/- ~5% can't be considered "close enough", then formal testing of some form or another is called for, and you might as well ignore the normalized power data entirely.

acoggan said:The normalized power algorithm is pretty good, but tends to overestimate actual sustainable power during shorter efforts in which anaerobic capacity can play a significant role. That likely explains the 5-12% overestimation you seem to have observed. Given your apparent decision to use 20 min power as the metric by which you judge your metabolic fitness (which I definitely donotrecommend), you should rely on the average power, not the normalized power.

Not sure I follow here. Is 20 mins considered a "shorter"effort for which NP is not a good indicator ?

Surely by estimating FTP @ 95% 20 min NP we are doing the same thing in using a 20 min effort as the metric to judge met fitness ?

I routinely use tjhis %ge of a 20 min max effort to estimate and measure FTP - am I wrong here ?

peterwright said:Not sure I follow here. Is 20 mins considered a "shorter"effort for which NP is not a good indicator ?

Surely by estimating FTP @ 95% 20 min NP we are doing the same thing in using a 20 min effort as the metric to judge met fitness ?

I routinely use tjhis %ge of a 20 min max effort to estimate and measure FTP - am I wrong here ?

Let me try answering your question(s) this way: the minimum duration over which I'd recommend placing trust in normalized power depends upon:

1) the purpose for which you're using the number,

2) the precision that you need/expect (related to #1), and

3) the characteristics of the individual (relatively high neuromuscular power

So, while 95% of 20 min normalized power might provide a reliable estimate of functional threshold power for one person, for another it might not, either because the algorithm tends to overestimate under such conditions, or because that particular person's ratio of 20 min to 60 min power is significantly greater than or less than 0.95.

Does the above make sense?

--Steve

ZimboNC said:

--Steve

That is correct. However, it is worth emphasizing that Hunter recommends using 95% of average power, not 95% of normalized power (which therefore implies that you should use a course that results in a low "variability index", i.e., ratio of normalized power to average power).

acoggan said:Let me try answering your question(s) this way: the minimum duration over which I'd recommend placing trust in normalized power depends upon:

1) the purpose for which you're using the number,

2) the precision that you need/expect (related to #1), and

3) the characteristics of the individual (relatively high neuromuscular powerandrelatively high anaerobic capacity appear required to "bust the algorithm").

So, while 95% of 20 min normalized power might provide a reliable estimate of functional threshold power for one person, for another it might not, either because the algorithm tends to overestimate under such conditions, or because that particular person's ratio of 20 min to 60 min power is significantly greater than or less than 0.95.

Does the above make sense?

Yes - thanks. I generally use either a PT300 indoor or a steady hill - so VI is low and it seems to provide a fairly good estimate. I then allocate zones as per CP but adjust quickly as we start sessions. Seems to provide a good starting point.

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