Thoughts on Wprime, anaerobic capacity, 6min power, and criterium races!

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Thoughts on Wprime, anaerobic capacity, 6min power, and criterium races!

Рет қаралды 21,287

Күн бұрын

I do not use the critical power model at all when working on issues of training intensity distribution. However, I do think the CP model is very interesting conceptually when trying to understand high-intensity repeatability and energy distribution during those variable intensity races like cycling criteriums or hill XC ski races (see Skiba et al and Losnegaard et al for some nice work on W' recovery during stochastic races). So, this is some "thinking out loud" aided by some calculations to explore how these concepts all connect in practice.

Пікірлер: 19

@christianmieen2887 4 жыл бұрын

Dear Stephen, that sounds really interesting. I am about 72kg and I have similar physical capabilities. However, on good days I can do those values in your red zone, e.a. 1min 800w or 35s 960w.... i can kill myself for days doing these attemps. Seconds point, which is more interesting, the recovery rate of W'. The whole communities focuses on continues power testing, like 3-20min maximum power output. But when you look at a normal road, mtb or cx race, it just the whole time peak and pause for different intervals depending on the discipline. Have you ever thought of creating a test to meassure the ability to repeat anaerobic afforts and to derive the w' recovery rate from that.

@gerrysecure5874 6 ай бұрын

I got my first PM in 2006 and soon thereafter stumbled across Monod Scherrer. It worked perfectly for me and I use 5min and 20min test with 10min break (Hunter Allans protocol). Then the resulting CP matches my verified one hour power (ftp) perfectly**. Since then I use this to test FTP. Nothing works better. ** Theoretically according to the model I should be able to hold CP(60) which is CP + W'/60 but the work/time curve flattens because we are no machines. So the model is great, but applying common sense is not a mistake. Knowing W' in different fatigue states definitely helps to manage intense efforts not overreaching during a break away or final last minutes in a race.

@vingrirr 4 жыл бұрын

can you provide a copy of the excel sheet for us pleabs?

@XX-is7ps 3 жыл бұрын

Came here to post the same thing, I'd love to see some of these spreadsheets/analysis made more available

@peteranderson6935 3 жыл бұрын

I've had mirror thoughts on crank length. There's a recent push to shorter cranks on lab measurements of efficiency, FTP, comfort and so on. But I use 180mm even in a crit. In a bike race you're either off the front, in the wheels, or off the back. When you're in the wheels you can ride a shopping bike complete with front basket. What counts is what you've got available when you jump, or someone else jumps; it's that real high end and how long you can hold it for, and how often you can repeat. I find long cranks are better for that.

@chrissheldon2681 Жыл бұрын

Lol you must not corner much, I’d be terrified to crit race on 180s, you just NEVer get to pedal out of fast corners

@velo1337 4 жыл бұрын

not sure if a linear formular for Wprime can be plotted into a non linear graph (like the power duration curve). thats why sometimes for wprime 20 is right sometimes 26 somtimes 35... since its not linear

@hallo108 4 жыл бұрын

Wouldn't 20 min effort be a bit to long for the CP-model? From what i remember reading about CP, the model says you can use steady sate efforts ranging from 2-15 min and that you are required to reach VO2max during the efforts for it to be valid. I think one of the reason the model wont work with short efforts and sprints, is that it can't account for the rate off energy release and how fast you can pump H+ and lactate out of the muscle fibers during the shorter efforts. Then on the longer efforts the model can't account for the buffering of H+ through exhaling of CO2, since that in a sense would increase the total anaerobic buffering capacity and Wprime.

@sportscientist 4 жыл бұрын

Well, I was trying to be forgiving in my interpretation of the model's utility. A 3-15 minute predictive validity window is, strictly speaking, more defensible for steady state events. The utility of the CP/W' model for stochastic events is unclear but interesting to investigate. It does seem like that a maximal duration for this type of event will be associated with glycogen depletion. So it might have utility for a 40min criterium and a 90min soccer match due to different rates of glycogen depletion.....

@nicolalunardon9118 Жыл бұрын

Morton’s model would be a better choice in that it would allow to sharpen the red area

@robertchung4914 4 жыл бұрын

So, what you're saying is that fitting a two parameter model with 3 observations and then extrapolating out of the range of the data isn't optimal?

@sportscientist 4 жыл бұрын

Strangely, it seems that the underlying assumptions which make the model valid for predicting maximal power within this 3-15min (or 20) window are just not valid for continuous efforts lasting 60min. So, adding additional, correct, power for duration values far outside this 3-20min window from an individual power duration curve actually give you CP/W' estimates that are no longer useful for predicting "anything."

@andyfron 4 жыл бұрын

@@sportscientist It is a useful *interpolant* between durations. It is not a good *extrapolant*, as you have done with the 1hr example.

@robertchung4914 4 жыл бұрын

@@sportscientist I wouldn't have said that. As Andy has pointed out below, it's a good predictor of interior points, not so good when extrapolating. There're a couple of statistical issues involved, but also a larger philosophical one, which is sometimes called "reification." In essence, you're estimating parameters of some model and then imbuing those estimates with a special significance, or reifying them. This has happened in many fields, I'm not singling ex phys out. Estimation of a 2 parameter model with only a few data points is a different issue, but even then you can do some examination of the robustness of the slope and intercept. FTP is a one parameter model. W' and CP form a two parameter model. But in either case, I like to cite Sam Karlin's "the purpose of models is not to fit the data, it's to sharpen the questions." In that context, your color-coded table that shows what's physiologically unattainable is a sharp question.

@brokengames9020 Жыл бұрын

care to share the spreadsheet?

@andyfron 4 жыл бұрын

Thanks for the insightful presentation, Stephen. I'm still not sure what to think of the notion that there's no infinite-duration power level. As a counter-example, I would use the Young Shuffle practiced by Cliff Young to win the Sydney-to-Melbourne Ultramarathon in 1983. Constant "running" power for five days, 15 hours and four minutes. For me, that's a long enough duration. :-) ( Ref: en.wikipedia.org/wiki/Cliff_Young_(athlete) ) You mentioned that everything from 6min to 20min fits the model, but that 1hr doesn't. Have you tried fitting a CP-model that includes a reconstitution parameter? I'd also be curious about what your CP30 and CP45 looks like.

@robertchung4914 4 жыл бұрын

Right. I've long thought a renewal model (with a reconstitution parameter of some type) could be warranted.

@sportscientist 4 жыл бұрын

Yes, there are events like the RAAM where you can almost say they achieve a quasi steady-state at some specific power (150W for example) for many hours to days. The point is that the CP model says nothing about what this truly sustainable power output is, and it cannot do so because of underlying physiology.