Garmin app Focus and Strain has field called difficulty. Same thing can be seen on workout graph. I wonder, how can it be used in training, progress, in real time on Garmin? Can it be compare to Intensity factor? I know, that its EWMA of XSSR, but its hard for me imagine what kind of “hardness” is hidden under that number, because its computed much more difficult than TTS, where one cannot reach more than 100 and IF .5 is half of FTP. Here is XSS subdivided into low (XLSS), high (XHSS) and peak (XPSS) repeated effort under fatique can make XXSR even higher. I looked at a few workouts and with difficulty around 50 is my XEP is at 75% of TP.
Can this figure be any useful being on garmin datafield or later by analyzing graph?
The way I personally view difficulty, is that, in the main, you want to get as much XSS as possible for the least difficulty. For example, there are many ways to accumulate 80XSS - but why do it in a difficult way if you can do it in an easy way.
However, doing more difficult sessions are useful for a couple of reasons:
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It is good practice for digging deep, that you will need in races. ‘Hardness’
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If you can cope with more difficult sessions, it unlocks a wider variety of workouts that stress the energy systems in different ways. This is where the star system comes in - very well trained athletes will be able to cope with higher difficulty sessions - they may then have the ‘luxury’ of doing a 40 min workout for the same XSS as opposed to an 60 min one.
Not sure if this is the Xert take on it, but it seems to make sense to me personally.
Our very own Dr. Stephen Cheung wrote an article a while back for Pez Cycling that talked about the difference between Fitness and Repeatability, which I think can relate to difficulty score. In general (with an accurate signature), completing a 4 or 5 diamond difficulty workout will be very difficulty (or impossible) to complete for a 1 or 2 star athlete. So it seems that chronic training is related to one’s ability to tolerate “harder” efforts.
I don’t think there’s any relationship between XEP and difficulty. However, James had a great comment above that you want to maximize on the strain you can accumulate while minimizing the difficulty. This isn’t always possible, as inevitibly the only way to increase the strain/hour is to increase the intensity, or perform an easier effort after drawing MPA down (both of which dramatically increase the XSSSR, which in turn quickly raises the DS). I think it’s useful for identifying incorrect signatures (generally anything above 200 DS may indicate that TP is underestimated), and seeing how you’re able to tolerate harder efforts. Hope this helps a little bit!
Such an effort would then (almost) always result in a BT?
Usually, but not always. I usually see this from Zwift races where MPA gets pulled down in the first min and then the remainder of the ride is completed around threshold.
I have only 6 of > 200, 3 of which are long (1:40 - 2:10) and 5 resulted in a BT. The other one was near, even showing an over MPA effort, but probably not long enough.