# Difficulty Score?

I am trying to understand how Xert determines a Difficulty Score?image|690x388

The image with more intervals at a higher wattage has a lower difficulty score than the shorter session?

In the top image, are those shorter intervals longer and the recovery periods shorter than in the second image?

Look at how the MPA drops if you see it dropping further in the top file that would be why the difficulty is higher.

the top image is 1min @400w with 1min RB
the bottom image is 1min @420w with 2min RB overall was far more difficult to complete

Here is the same 1min @400w with 1min RB. Proceeded by 4x3min at 340w with 2min RB and it also had a lower difficulty score??

the lower difficulty is the longer workout because there are only 8 microburst intervals stacked against each other as opposed to 10 microburst intervalsâ€¦
I would tend to agreeâ€¦ doing 10 back-to-back is much harder than doing 2 sets of 8â€¦ like at least for me i can recover, and the second set wonâ€™t be any more difficult than the first set. though obviously itâ€™ll be more kJâ€¦

haha i should caveat to say that it might not feel easier to everyone! and I havenâ€™t tried something that difficult before i donâ€™t thinkâ€¦ at least not in a indoor workoutâ€¦ So iâ€™m only guessing and you actually did it! so i IDKâ€¦

For me the 10 back to back 1 min efforts with 1 min RB was easier than the 2 sets of 8

are you sure it is lower? they look the same to me since difficulty score is the highest difficulty reached during the workout right? doesnâ€™t say anything about the volumeâ€¦
both difficulty graphs peak pretty much exactly under the same 100â€¦

as to why they could be exactly the same difficulty scoreâ€¦ apparently the hard threshhold intervals do not influence the exponential weighted average?

And that is why I am asking the questionâ€¦what is the purpose and how is it calculated? If it has noting to do with volume then theoretically someone could make a massive short effort and have a difficulty score higher than someone doing and hour of 1on1off at 200%FTP

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Reproduce those interval sessions in the Workout Designer and you can see what happens to MPA and the Difficulty Score. Small changes to intensity and interval/rest lengths can make big differences.

Difficulty score is meant to represent exactly what it sounds like - how hard was your ride/workout? It also seems to somewhat align with central fatigue (fatigue that isnâ€™t directly related to muscular limitations - MPA), though it wasnâ€™t designed to do that. Itâ€™s calculated as an EWMA of XSS/hour

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