Good morning David,
Do you know why on the power page my old power curve would show a higher W’ value than my current power curve, which has much better power all around? Based on the math the W’ should clearly be better with the better power curve right?
The difference in CP is huge. Maybe the one from last season was underestimated, maybe the one for the current season is overestimated. But W’ changes massively when changing CP/FTP/eFTP because it is the work above that limit.
Yeah I am a new rider, only a few months so the growth is pretty quick “newbie gains.” It won’t last much longer.
The W’ from the smaller CP was 4k larger than the W’ from the larger CP - that’s why I’m confused. It seems backwards.
I assume they are both under estimated because I regularly go very negative in races and I have it manually set to 17k - which is obviously much larger than 10k and 14k
Nope, higher CP automatically means lower W’ because you will do less work above CP.
Suppose your FTP (CP) goes up while training but you’re not aware of it because you haven’t tested. In that case it will feel easier to work above FTP/CP, and you will get a higher W’.
That makes sense, but my FTP is 212W (accurately set by Intervals from my max efforts in Zwift races) and my W’Bal set arbitrarily at 17kJ still went negative.
Wouldn’t that indicate that either my FTP is wrong (which I doubt) or my W’Bal of 17kJ is too low (most likely)? Or is there a 3rd option possibility?
Btw thank you for helping me figure this out! I appreciate your time and knowledge! W’Bal is a very interesting concept and I’d like to dial it in
W’ is not an easy metric. You should not give it to much thought. What you can say is that people with high W’ have a bigger anaerobic capacity, think sprinters and guys that race up short steep hills.
The W’ concept has a lot of flaws. First of all, there are 2 different calculation methods, differential and integral. The results are quite different. And then there’s the ‘recovery’ phase for W’ which is based on an avg constant but can in practice be quite different among different athletes.
These things have been covered already on the forum.
And an interesting chart that is available as a custom chart is the Veloclinic plot.
For sure, all metrics are just helpful insights to help guide and view progress. My thought is that as long as I have a consistent method of analysis it is another useful metric to measure progress. Especially since my strength is in sprinting, increasing my W’Bal would be a valuable addition since I would be able to extend my sprint reach and start earlier than others.
I’ll take a look at the other discussion - thanks!
You need to get to the finish having expended as little energy as possible, then use the sprint strength to kick from there. Increase your FTP/CP so that you’re riding below threshold in the lead to the sprint.
Gerald 100% - couldn’t agree more! 
I think W’Bal has an additional (and interesting) new perspective on that concept though.
Yes increasing FTP helps get you to the finish line in a healthy spot, but having a larger W’ Balance will enable the rider to attack the sprint further out from the line than others.
Increase FTP to keep your Balance full and increase your Balance tank to extend your effective sprint distance 
