After reading lots of “stuff” on W’Bal and CP I think that this is the easiest answer….
All of the mathematical models of W’Bal (2 or 3 point models) are inaccurate because they assume everyone is the same.
The best way to gauge YOUR W’Bal is to get a relatively accurate FTP and then go all out on a ride - review your W’Bal after the all out effort and adjust your W’Bal so that you normalize your value to 0J at your peak depletion.
Does anyone see any issues with that particular method? Other than it isn’t as sexy as a mathematical model
And even then, if you do multiple hard efforts with some recovery in between, it might still be significantly different compared to one all out effort.
But if you do the same protocol each time you ‘test’, you may be able to extract some useful information.
Good point, it would have to be an iterative process across many max efforts (naturally some will be long single efforts and others more choppy and repeated efforts), but in the midst of the many data points there should ideally be a linear trend upwards of an increasing W’Bal.
In fact, I was just looking if I could look at my max W’Bal depletion per activity and did not see an option for W’Bal depletion - can that be a metric to add in the future? I’d love to see how that value changes overtime
For example, this activity would have shown a max depletion of 23.8kJ (17kJ - (-6.8kJ))
Is there a reason why my W’ Balance would empty on a max 6 minute effort (I set the W’ Balance value based on this, 25.5k I think) and it goes to 0 at the end of my 6 minute test.
Doing Vo2 sessions today, 3x8 and on none of them do I even get close to 0, even though at the end of the 3rd set I am literally done. I don’t think I could have done much more work above FTP, certainly not the 13k that I supposedly still have left in the tank.
Quickly checked last year, same story, did a 6 minute test, where I deplete about 23.4k (a bit higher but it’s 23.4k if I set FTP to eFTP which is slightly higher so I went with that for that exercise) and the test ends at 0. I did some 8x3 the week before and even though I know I am always done at the end of those, the last set ends with supposedly 13k still left (the 13k both times may be coincidence, I also rounded a bit). How is that possible? Surely one should be at 0 if one can’t go above FTP anymore.
It’s worth remembering that you are dealing with two models here, both of which may not be great at representing your physiology:
(1) The Critical Power / W’ model from which you have got some values that represent your current fitness level. You haven’t stated how you determined your FTP, but you have said you have determined your W’ from just one effort - this may not be the best way to determine your W’. There is quite a lot of academic literature out there looking at how an individual’s CP / W’ can vary significantly by choice of defining tests. If you want a read, here is one, admittedly quite long!
(2) The W’ reconstitution model, which has been discussed in a number of threads (here’s one) and is not tuned to your actual recovery abilities which likely differ to the standard assumptions.
As for what to do with that information, for me it depends on what you want to use W’ (balance) for. If it is just for tracking your fitness / performance over time, and if you are testing in a consistent manner, I don’t think it matters if you see significant variance from W’=0 when you are actually completely spent from above threshold work. If you want to use it to help gauge how much you should have left in the tank as during particular types of rides, you may want to look at different protocols for determining W’ (and CP). That could be different tests (duration, quantity, etc), doing your 6 minute effort after you have already done a certain amount of work, or something else.
Yes I suppose my aim was to use it to see if I get the maximum out of myself, and if certain Vo2 protocols do this better than others.
Yes, I think my recovery abilities are probably lower than what is assumed. And if I take the FTP/W’ values from Golden Cheetah, 243 and 21.1k, then yes the 6 minute max effort goes to -3.3, and the 3x8 doesn’t go near 0, but the 30/15s look pretty good, very good even if the recovery is over-estimated by a few 1000.
But you are right, it shouldn’t be necessary to get it to 0, but as long as I do it consistently, I can still compare across efforts.
When I read the article related to the W’bal (HighNorth), I saw that we are all using very high numbers of W’? 25-35kJ values to deplete to 0 after some all-out effort intervals. These should be numbers of “the other end of the spectrum”-cyclist (sprinters). “Normal” endurance cyclists should be in the 9-15kJ ballpark.
I am not sure I personally will pay much attention to this metric. I did another 5.5 minute max effort and even though I raised FTP value (which will lower work above FTP all else equal) and slightly raised W’ to 23k, supposedly I was at -7k by the end of the 5.5 minutes. So I now have multiple efforts where I supposedly use up a lot of energy above FTP. Then I did a 11.5 minute effort and that supposedly ended with -18k. To have both end at 0 from 23k start (which note still seems very high given the text you linked to) I would have to be 270, respectively 274 watts CP/FTP. Current value set to 250. May be conservative, but not 20+ off. No way.
Additionally, the recovery estimate is just laughable. After 6 minutes I was supposedly back to 23k, but there is no way I could have done even near the same effort again.
I did a 20-min effort at 320W after 3,5hr ride. My (e)FTP (both) was set to 280W and W’bal at 20kJ. I depleted all W’bal till -27.9kJ. My eFTP auto-increased to 305W after this ride, but…
Not sure what I should have learned here? It was an all-out paced effort (9-10 RPE for sure), but I could still ride one hour extra, with some extra (although much easier, 1-3-min well above FTP) efforts along the route.
I’m curious what an extra data field like MPA or W’bal on my Karoo would’ve indicated during this effort? And more importantly, should I’ve listened to it
It was an all out effort within a bigger picture…
If you already did 3,5hr before and did another hour afterwards, you can do better. You are clearly in great shape, so if you want to have more precise metrics, do a full hour test to evaluate FTP.
For W’, you are missing the point. W’ is a metric to evaluate what you can do above FTP. If you ride exactly at FTP, W’ will not go down. Theoretically at least because the W’ concept has quite a bit of shortcomings.
First make sure to get a reasonable FTP estimate, then do a couple of max tests for different durations between 3 and 15 minutes, do repeats for the shorter ones. Only then you will get an idea of the W’ value.
As an example, re-analyse the ride you did but with the newly estimated FTP. You will see what I mean because W’ depletion will be only a fraction of what you have now.
Thanks MedTechCD.
It is indeed hard to grasp the W’-concept, to be honest. In particular, to use it as a training/racing parameter.
I use FTP% to build my interval blocks and use heart rate + RPE during the training/big rides to analyze if the power I put in is sustainable with what I feel and what my HR is doing at that moment. I found out about W’bal on intervals.icu and I’ve got intrigued to learn more
Do you use it as a parameter during interval training or race(like) days/Gran Fondo rides?
I’m only using it to get a rough idea what is doable when I design an anaerobic workout. Effort duration, recovery, intensity, number of repeats…
You can’t use it during racing because it is to variabel with length of efforts and recoveries.
If you stick to a protocol, it can show if you improve or not. But if you pinpoint it for a 12 min effort, you will be very surprised that it falls completely apart for 8 * 2 min interval workout for example. It can also show something meaningful for a training ride that you regularly repeat on the same course. If you put in a similar effort, RPE wise, you might see ‘real’ changes in W’.
This has been discussed before here on the forum and I think that only a very small number of people actually use it.