Critical power testing

fergie said:

So then should I enter 207watts as my functional threshold as this was the max power for 60min in January.

If you feel that ride was representative of a 'max effort' ride, then yes. Your FT may be slightly higher, but that's a good starting point.

There's a quick way to test it without necessarily doing another full hour max power ride. Do a couple of 20 min intervals at 207w with a fairly short rest (e.g., 5 mins). If the 2nd one is easy, it's probably understated a bit. If you can't hold 207 in the 2nd one, it's probably overstated a bit. If you complete the 2nd one with a high but manageable effort, it's probably about right. The cool thing is that just by doing various efforts of various intensities every day, you will eventually have a very good MP/duration curve, from actual efforts vs. computed from an algorithm.

fergie said:

Now I have a Powertap and CyclingPeaks which nicely tells me what my max power is for any duration do I actually need to do any critical power testing?

Seems redundant if CyclingPeaks tells me it already.

Those are just statistical estimates. Wouldn't you prefer to use your actual critical power numbers?

WarrenG said:

Those are just statistical estimates.

Wrong. What Fergie is referring to are actual values for average power over various durations, automatically extracted from the data by the software.

WarrenG said:

Wouldn't you prefer to use your actual critical power numbers?

There is only one critical power.

fergie said:

Now I have a Powertap and CyclingPeaks which nicely tells me what my max power is for any duration do I actually need to do any critical power testing?

Seems redundant if CyclingPeaks tells me it already. Possibly if I wasn't doing any group rides, threshold efforts, hills or was leaving the powermeter off for races.

That would depend in part on the duration under consideration and just how precisely you want to know your so-called critical power for it. Specifically, while you can generally get a good handle on your maximal power at very short or longer durations just by "cherry picking" data, at intermediate durations (e.g., 1-2 min) you probably need to do more formal testing to avoid underestimating the real answer.

fergie said:

So then should I enter 207watts as my functional threshold as this was the max power for 60min in January.

W/o having seen your data, I think about all that can really said is that your functional threshold power is at least 205 W (rounding to the nearest 5 W, 'cause you simply can't measure it any more closely than that).

acoggan said:

Wrong. What Fergie is referring to are actual values for average power over various durations, automatically extracted from the data by the software.

There is only one critical power.

Joe Friel mentions more than 5 different "critical power" levels. CP1, CP12, CP30, CP60, CP90, etc.

WarrenG said:

Joe Friel mentions more than 5 different "critical power" levels. CP1, CP12, CP30, CP60, CP90, etc.

I have a strong feeling that what acoggan means is that *for a given duration*, there is only one critical power.

Obviously there's far more CP-levels than Joe Friel mentions (as a matter a fact an infinite number), i.e. CP1, CP2, CP3, CP4, CP5, CP6, etc

_________
CycleFast

Joe Friel mentions more than 5 different "critical power" levels. CP1, CP12, CP30, CP60, CP90, etc.

I think that Andy is pointing to the fact that the real (Monod) definition for Critical Power is something along the lines of "a duration that can be maintained for a long time without fatigue" or something close to that. Friel kind of took the word Critical Power and turned it into a misnomer.


Greg Van Wagner

WarrenG said:

Joe Friel mentions more than 5 different "critical power" levels. CP1, CP12, CP30, CP60, CP90, etc.

Joe Friel usurped a term that was defined more than 40 y ago, and in the process created unnecessary confusion.

Again, there is only one critical power. It is variously described as "a power than can be maintained for a very long time without fatiguing" or "an intrinsic property of the aerobic energy system". Operationally, it is generally calculated as the slope of the linear work-time relationship for maximal efforts of >1 but <30 min (although I prefer >3 min, which is also recommended by some sports scientists), although there are alternative mathematical expressions that yield essentially the same value.

acoggan said:

Joe Friel usurped a term that was defined more than 40 y ago, and in the process created unnecessary confusion.

Again, there is only one critical power. It is variously described as "a power than can be maintained for a very long time without fatiguing" or "an intrinsic property of the aerobic energy system". Operationally, it is generally calculated as the slope of the linear work-time relationship for maximal efforts of >1 but <30 min (although I prefer >3 min, which is also recommended by some sports scientists), although there are alternative mathematical expressions that yield essentially the same value.

Apart from the terminology, are Friel's numbers simply different points on the MP/duration curve?

RapDaddyo said:

Apart from the terminology, are Friel's numbers simply different points on the MP/duration curve?

Yep, they're the maximum power that can be held for each of those durations.

There is only one critcal power. It's for the power for the time you are looking at. If it's CP60 then there is only one power for that 60min.

I can see how one can underestimate critical power if just using Cycling Peaks but I assume if you use info from the meter while training, doing group rides and racing you will be pretty close?

I also assume that if one is doing base then they may be missing a lot of the top end max data but if one is doing base then they should still be a way out from goal races and it's not so crucial to know your 5-60sec power.

Hamish Ferguson
Cycling Coach

fergie said:

I can see how one can underestimate critical power if just using Cycling Peaks

How's that, Fergie?

RapDaddyo said:

How's that, Fergie?

You simply don't go hard enough in training or racing to hit your real max for any given duration.

Hamish Ferguson
Cycling Coach

RapDaddyo said:

There's a quick way to test it without necessarily doing another full hour max power ride. Do a couple of 20 min intervals at 207w with a fairly short rest (e.g., 5 mins).

Did a 2 x 20 a couple of days after I got the power tap and got 233 for the first and 217 for the second. That's with pushing myself harder in the 2nd effort.

Should I be using NP instead of ave power? Which would make these scores even higher.

Hamish Ferguson
Cycling Coach

fergie said:

Did a 2 x 20 a couple of days after I got the power tap and got 233 for the first and 217 for the second. That's with pushing myself harder in the 2nd effort.

That pattern suggests that your FT is probably somewhat > than your 2nd effort, but < your 1st effort, maybe ~220-225.

fergie said:

Should I be using NP instead of ave power? Which would make these scores even higher.

Yes, especially if your power was variable due to, e.g., hills or wind changes. Guess you'll have to ride your intervals at higher power, huh? That's why celebrations of FT PBs are short-lived. You'll soon learn to defer PBs.😄

fergie said:

Should I be using NP instead of ave power? Which would make these scores even higher.

If most of the ride power falls within a pretty narrow (~10w) range, as on the trainer, I use avg power. If the power fluctuates wildly outside of that range, as it would outside around here, I use NP.