See question below. I created this topic.
Alex,
I’ve recently discovered TD after using TR (plus various other apps) for a long time. I really like it. I’m intrigued by the insights which W’ and CP can bring to above threshold work. But I have a question about which time intervals to plug into the Excel calculator as, depending on which ones I use, I get pretty wide ranging results. Which 5 time intervals do you recommend?
Thanks and please keep up the very good work.
Adrian
Adrain, let me make sure I understand the question. First you need to do a W’ test to make sure you know your W’. I need to create simplier instructions on how to do this. Once you know your W’ and your FTP/CP you just plug them in the workout creator. So I am not sure exactly what you are asking.
Here I just created a new good test for testing your W’
I was using the Excel spreadsheet you link to in the Blog - see below for the links - and entering power values for five different time durations. My question is which durations should I use? Because the results I get, for both CP and W values, vary depending on the inputs.
Blog page: https://trainerday.com/how-to-calculate-your-critical-power-cp-and-w/
Calculator used:
In case the EM Sports Science link stops working, here is a back-up to directly download the file
I hope that makes it clearer.
Just change the values in these two colums for these 6-values.
8-minutes will help determine your FTP/CP and 1 and 2 minute affect your W’ more. These calculations will produce very different results, it’s good to look at a mean-max power curve to determine them. Does this help?
That does help Alex, thanks. I have a pretty good understanding of my FTP (to ensure it’s close to the CP value) so can play around with the W’ number as I do workouts to refine that. But I’ll use the 1,2,8,8,8 intervals as a baseline.
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@amg61 Don’t know if you have a Garmin bikecomputer that supports IQ fields, but there are a couple IQ fields that calculate your W’ on the fly. I particularly like TrainingPower because you initially set W’ to a low value and it adjusts the value if you would go negative. You do however need a reasonably correct FTP for it to work as expected. Once you have your W’, the IQ field tracks what is left in your tank when going hard. So you not only feel, but also see when you will crack 
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@MedTechCD - thanks very much. I’m currently running a Wahoo unit but it’s good to know this is an option 