Using W balance

So if I did a ramp FTP test and I went negative in wPrime should I adjust my wPrime to zero out at the end of my ramp?
This is kind of a roundabout way of asking if a TrainerRoad ramp test will give a good value for wPrime.

OK so I realize this is a result of having the old FTP set as current. If I update the FTP on the activity to the new one I am no longer negative or just slightly negative.

This being said the TR calculated FTP is not the same as ICU eFTP due to my minimum sample time… This is where things get interesting, but that’s a discussion for another thread.

Yes Intervals.icu doesn’t recognise and use ramp test data properly yet. That is on the todo list.

2 Likes

Hi,

great addition!
I’ve completely emptied myself on a local, small climb, and I ended with about 0.7 out of 21 KJs, which makes me believe the 21 is quite right.

However, somewhere along the ride I paused for a while, which completely screwed my W’ (dips to -103).
That makes it quite hard to see where i actually went deep.

You can edit or delete the bad data in the toolbar just below the graphs. Then the wPrime should rescale.

Thanks Bogdan_Rylski. Could you eleborate a bit more, I’m worried I’ll delete more/other data than I actually need to.

I’m assuming the stop is when you have the positive linear slope. The way I would go about it is add a speed graph, get time stamps from the beginning and end of the stop and delete all the power data from that period.

Thanks, I guess I fixed it.
I put down some Watts after stopping for about 10 minutes, and I guess the algoritm (falsely) filled in the blank spots prior to that with that same wattage (which was above my FTP)
Fixed now, thanks!

1 Like

Yup, here is the GC screenshot of my W’bal for that ride 04 Jan 20.

An interval near the end drags me down to a fairly low W’bal… I just looked up this ride and it was an FTP test! The Sufferfest uses a different approach than the 2 x 20 min test, trying to assess power over shorter durations (plus FTP) - they call it 4DP for 4 dimensional power. That big drop was the 20 min portion of my test - I guess that I could have gone a little harder…

1 Like

I need to fix that. Need to put a limit on the drop from one time tick to the next.

1 Like

Hi @david - don’t know if I’m doing something wrong but I can’t get the W’bal chart to appear on my activities. See screenshot below - the other ones I’ve ticked have appeared but not that one.

(I’ve refreshed page to make sure I’m on latest version)

Actually don’t worry, I’ve figured it out and entered my W’bal.

One point I would make is from a UI / UX perspective, if you’re batch editing workouts, I think it’d be quite easy to overwrite the FTP and weight as well. Perhaps the default should be to have all the fields blank, so you only edit the ones you enter data into.

1 Like

I agree. I will change that.

1 Like

is it possible to have w balance in the custom charts on fitness page ?

Do you mean the W’ number? I can add that easily.

Yes if that’s the same as you work balance calc Would be interested to see it daily on chart.

This is live now. Look for “W’” at the bottom of the plots list.

1 Like

Thanks David, now i just realised need to do longer bulk edit backwards for activities. I’ve noticed a substantial difference though in Mortons 3P verses power default, 28kj or 45 Kj values. Not sure what is right, I’ve recent 1m, 5m, 10m, 20m efforts.

1 Like

Mortons 3P is the one to use for this if you have the correct inputs. The default algorithm uses pre-defined curves i.e. it assumes everyone on the same FTP has the same W’. This is fine for FTP estimation from single max efforts but not if you want to track W’.

1 Like

So, this is possibly a general question about W’Bal rather than about Intervals, but here goes… what, if anything, is the relationship between W’Bal and your power curve?

The reason I say that is that if I take my curve-predicted power at 8 minutes (316), and my current FTP of 276, that gives me a Kj output above threshold of approx 19200.

But if I take my curve predicted power-output at 2 minutes (416), that gives me a Kj output above threshold of approx 16800.

Which means that if I do an all-out 2 minute effort, the W’bal would not show me going down to zero.

First question, am I missing something here? Or is W’Bal always going to be less accurate at different power levels?

Second question, is there a way you could create a flexible W’Bal from your power curve and apply it intelligently to rides? So it isn’t so much of a simple “this many Kj available above threshold”, but more “what % of my resources at this intensity have I burned through?”. Might be an impossibility, but worth asking!