Hi, I will like some input on w’ . Yesterday I did an all out 5min interval. And checking the graph I went below what I had as my w’. Does that mean that I did more work than what I was supposed to be able to? Does that mean that I need to review my critical power and w’?
Hi Jorge,
yes, thats basically what it means.
If your W’-work becomes negative, your preset CP is to low, or other way round, your CP has increased and you getting stronger.
some basic literature
cheers
alfred
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thank you very much
What is the suggested way to compute the W’?
Hi David, what I understand, is that there are some Critical Power and W Prime calculators out there. You would do 3 to 4 all out tests between 3 and 20 minutes in length. The power you got from those tests is the input to the calculator and that gives you your CP and W Prime.
Here is one I found: https://www.highnorth.co.uk/critical-power-calculator
I did a 3 - 5 and 12 mins test to get my results.
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How do you know your W increased, and not your FTP? Wouldn’t higher FTP mean you do less work above treshold at the same power, hence depleting W less?
typically they are correspoding to each other. if your W’Prime increased, then usually suggested that you also increase your FTP.
basically, if you have FTP of X and your W’Prime of 10kJ
but you did a super hard ride and you found your w’prime went down to -5kJ this means you did more work over your FTP.
The calculator will give you a CP and a W’ . The longer and higher you work above CP the faster you deplete W’. If your CP is 280w and you have 15kJ of W’ of work above that CP , the more work you do above that 280w line depletes your capacity, and you will need more time to recover before you have enough in the tank to go again.
CP takes into account two or more values to construct your own graph, or line that establishes a relationship between power and time to give you approximate values of your own capacity at specific power.
The W’ that the calculator gives you is derived from the relationship between the different values that you got for the different efforts to construct the CP. If you have a strong 3min versus a weak 12m effort that will affect the CP and W’ values.
A higher FTP could be, as you say, the consequence of better efficiency at a determined power. The amount of work done is the same, because power is work done for an amount of time, but it could be less taxing on your body.
So imagine you do three CP tests 4 months apart from each other. The first one gives you CP=280w and W’ =15kJ And the second one gives you CP=270w and W’=20kJ and the last one CP=300w and W’=5kJ . During this time your FTP probably is very similar, but your work capacity between 270w and 300w is very different. If you compare the second and third tests it is very obvious that during the second one you are very efficient around 270w with great endurance around that power. on the other hand the third test implies that you could be better at shorter efforts but lack the efficiency for working close to that power. That is the trade of different training objectives.
For most riders CP and FTP will be close. If you really want to know if you improved FTP or if your work capacity above a specific threshold increased - W’ -, you should test that in separate ways.
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@David so is there a feature request to add automatic calculation of W’ based on power curve data? I’m pretty sure this is basically the Xert MPA, which they have a fancy widget that shows me this info in real time on my head unit.
It would be cool to have this metric show up in Intervals and adjust to help you plan your workouts be estimating this dynamically.
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Oh, W’ is calculated on the power curve! I missed this.
@David I didn’t see anything in the features request for W’ or CP, is this something that could be populated into the workout builder, or a setting to have it use the current value automatically in your settings instead of it being manual?
I’ll throw it in the features request forum? Should I just do that anyway instead of tagging you? 