This is a good point, in general. But you can reproduce the numbers in the paper based on the equations.
There is an error with the paper that was pointed out on the Xert forum, but it has to do with Figure 5A-D.
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I suspect the Intervals.icu implementation is going to get quite a bit of scrutiny from @GarageLab and others on the forums. So hopefully it all works out.
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Does this mean my meathead workouts will finally help my “fitness” 
Thanks David!
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Why not use power-curve values as default – documenting the caveats, as you typically do with little popups – but allowing advanced users to override the values with their manual FTP/W’ values…
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If people regularly do test for defining their lactate curve the limiars could be used to define the contribution of each energy system. True?
I’m excited to see this. I’ve been using both XERT and intervals in tandem lately, and must say getting to know the XERT platform has pushed me to think about quantifying / progressive overload of the specific energy systems in a lot more detail than I had done before. I also think XSS is doing a better job of predicting how taxing a ride is than TSS does.
For the reasons you mentioned, I don’t love the idea of having the platform automatically changing FTP and W’. I like seeing when the estimate is changing, but small changes doesn’t matter than much for tracking load, etc. and a lot of the times the estimates are just changing because of the type of riding being done and not doing many max efforts at well-rested appropriate time-intervals to get a good estimate.
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I am thinking about solving the “where to get the power model parameters problem” by using the captured FTP (for CP) and W’ values and adding one for pMax, then implementing the much requested feature to optionally update these automatically.
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We have added user editable “Pmax” to sport settings (to go along with FTP/CP and W’):
This is copied on to new activities and can be edited per activity (like FTP and W’):
If you are using your own layout for the activity summary you need to add it.
You can also add it as a column to the activity list view and edit directly on the grid. Or use Edit → Edit to bulk update activities:
As you can see “Strain Score” (like XSS from Xert) and its 3 components are also available. It seems to generally be quite a bit higher than TSS (“Power Load”). For me this is true even for easy Z2 cruise rides. Not sure if I have something wrong or that is just how it is. Would be better to more closely match TSS especially for multi-sport people. This is only for cycling.
Those settings are all live for everyone now.
The activity stream charts are live for people who have enabled beta features (near bottom of /settings page). There are charts for MPA, strain, aerobic, glycolytic and PCr and one with MPA and Power. You can edit the model parameters (FTP, W’ and Pmax) and the charts update.
Now add similar stuff to the workout builder and to figure out how to update FTP, W’ and Pmax automatically, like eFTP.
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Am I blind? Just can’t find the Stream Charts to add?!? 
Beta Features active, Strain and other values shown on Table Activity View.
nevermind 
was looking in Chart → Search, Activity Charts → Search … but just noticed it’s not in Search but on the Main Page of Charts … 
Having a look into this really interesting feature now!! #excited
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For me the strain score is approx 20% more than TSS for easy rides and much closer on the really hard ones (e.g. races). So likely multi-sport people using this for load will have to accept that it will bias their total load a bit more towards cycling.
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Would ISS be a good term to use for Intervals Stress/Strain Score?
Will probably stick “SS” for “Strain Score” since that is the term used in the paper.
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@david Can we plot this Strain Scores, CP, W’, etc… in Fitness tab?
I didn’t find a chart or the option to create one.
Thanks
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A recent (detrained) easy ride comparison of mine
Intervals
FTP 191W
TSS 56
SS 52
Xert
TP 186W
XSS 51
Tx. We just fixed a bug (will deploy Thurs AM) that rounded some things up so your XSS should match exactly no.
Have added per interval stats for strain and 3 parts. Will sort out fitness tm.
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hi a doubt, do you prefer use TSS , instead of Trim or Bannister, for your workout load calculation? have you share yout thoughts?
The rounding bug has been fixed and strain score is now available per interval. You need to re-analyse existing activities.
The layout editor was little buggy since the big update. It should work properly now. You can add the strain score metrics:
Click them to get help and link to the paper:
You can also add matching per interval fields (click “Fields” under the timeline chart). You can see the values for my interval on the bottom left of the screenshot.
You can plot SS and its components on the /fitness page:
It seems I only really train glycolytic and PCr in races. Maybe I should be less lazy and the races would go better?
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The auto-updating of values is the big one for me here, thanks!
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