Useful WBal chart?

Hi,
How sould I read and interpret the WBal chart ?

Thanks

Try this

There’s lots of info there. Tho, like me, you may be still be overwhelmed.

Give this article a read, it quite comprehensive, including how to test your CP.

… so as i interpret it … if your W’bal is gone into minus under zero, your FTP-setting or your W’bal setting is wrong…

But if i can say it from my standpoint i have no idea how i can feel/check my correct w’bal.
I only can feel/check if my FTP-setting is nearly correct… and if my FTP is correct than i could be relativly sure that i can change my new W’bal (old W’bal + that amount what went in minus) as my new one… am i right there?

Nice and clear article, but they don’t mention another important factor, namely recovery time constant.
I’m pretty sure the test as described in the article will give good results for estimating a single hard effort. But for repeated efforts, there is the unsure factor of W’ replenishment. The calculations for W’ use a Tau constant for replenishment and Tau is not the same for everyone.
As a matter of fact there are 2 different versions of that, the integral and the differential version. Those 2 give quite different results, depending on the W’ replenishment speed.
Meaning that during a ride with multiple repeated efforts, your W’ might go negative, or you will not be able to fully use it. Don’t change your settings in that case, because you will never get a perfect result for “real life” cases. Use the calculated numbers for single efforts or to ballpark the intensity you need for eg. VO2max interval training.

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this week i’ve kind of got lost on W’bal also.

made an effort just to see if i could update my eFTP. a full, consistent one. it did generated an eFTP, but the W number for the ftp was very far from the W calculated for the activity… one was 18 something, the other 23.

shouldn’t both be correlated?

Never take W’ into account when doing work close to FTP. It just isn’t made for that. Example: if you do a 1 hour FTP test, W’ will almost not move from 100%. So W’ is telling you in this case that you were doing an “easy” effort. Not really correct is it?
Use W’ for VO2max and higher intensities.

nevertheless, i’ve got 2 very different w numbers extracted from that activity. the isolated one gives me how much i’ve really depleted the tank, the other a suggestion based on the eFTP. which one do i take as a reference for training?

If the one where you “depleted the tank” is really a point where you went to failure, I would take that one.
The suggestion based on eFTP is an estimate where your PD curve is compared to known PD-curves with FTP/W’ values. Not necessarily your exact values…

CP can also work better than FTP for setting training zones if you’re anaerobically stronger or weaker than the ‘norm’. That’s because common FTP test protocols (such as the 20-min test and the ramp/step test seen in popular indoor training platforms like Zwift and TrainerRoad) make assumptions about the extent to which the anaerobic energy systems contribute during the test, and can sometimes produce FTP estimates that are out by as much as 10-15%.

The bit in bold is common across a lot of cyclists. Inaccurate FTP based off the 20-min and ramp test.

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just trying the metrics produced by intervals estimations to see how it works and if it makes sense. so it wasn’t a 20min or ramp, was the calculation base on a shorter effort, the eFTP pd-curves based estimation.

will try the w estimated from the activity itself.

Just did a CP3 All Out Test yesterday… so to say a 3min sprint with maximum available power all the time (nearly died :sweat_smile:)… so you guys think thats an useful w’bal value?

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@Andreas_Fitz
Your power dropped off over time, but should have become more stable towards the end of the three minutes [well done]. If your power did indeed stabilise near the end, then your average power for the last 10-15 secs is your critical power. See The 3 minute all-out test - YouTube for a full discussion.
So yes, this is how you estimate your CP and W’. W’ is the total amount of work you can do above CP.

@Michael_Webber thanks, that’s exactly the way i did it, and the last 10s was around 283W…
When i set 283W as my FTP/CP to calculate W’bal i get a value of 21.6kJ.
But when i set my more realistical FTP/CP of 270 to calculate i get a W’bal of 24.1kJ.

For understanding, just to get a good value of my w’bal i have to use the last 10s of my CP3 All Out Test!?!

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@Andreas_Fitz
I know that David writes “Anaerobic Work Capacity or W’ (W prime) is the amount of energy in Joules you have available when riding above threshold (FTP)”, and presumably calculates depletion in this way.
But the physiologists – including those who formulated the 3-minute test – take W’ to be the amount of energy available above CP. And, given the usual rough definition of FTP as the maximum power you could hold for 40 minutes or more, CP > FTP – how much more, depends on you. [Also, CP > Max Lactate Steady State.]

Now, on your test, you did a certain amount of power each second:
total work = p1 + p2 + p3 + … etc, as indicated from the power trace on the main activity page. W’ is a proportion of the total work [409 kJ]. What proportion? It is estimated as the power above CP each second:
W’ = p1-CP + p2-CP + p3-CP + … etc. Add all these seconds of power up to get W’. You don’t need to do this [David kindly does it for us], but it is obvious from the formula that the higher you estimate CP to be, the lower W’ will be.

Obviously, the way you estimate CP is critical [!]. If you look at your power trace over time on the main activity page, it likely starts off falling steeply [perhaps after a few seconds], but the fall become less steep as time goes on, eventually becoming more or less flat. What you want is the average of that ‘more or less flat’ bit. Usually that’s about 10-20 seconds’ worth.

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I am overwhelmed with all these information and calculation !!