ICC said:
This cardinal feature is a pathological inability to produce sufficient energy on demand
This is already an interpretation.
My point was just that I think CCC/ICC require muscle issues.
It's an and/or criteria which accepts mental fatigue as valid without physical fatigue.
CCC require muscle and physical fatiguability (just "and").
ICC require points 1-5 fulfilled to have PENE. Point 1 includes "physical and/or cognitive fatigability", point 5 "Low threshold of physical and mental fatigability". Later the authors speak about "weakness". Altogether, muscle issues are a part of PENE. But, in my view, it is not as clear as in case of CCC (in fact I find it confusing, that points 1-5 need to be fulfilled, in point 1 physical fatugability is optional, in point 5 it is mandatory; I can just speculate that's not what the authors intended).
Stating that 'muscle fatigue is common' is also stating that there are exceptions,
Well yes, Ramsay-ME uses not the same criteria as CCC/ICC, I just find it interesting. Something to consider.
By the way, for me this is not about excluding anyone. I just don't think it is correct to say "a CCC/ICC-ME diagnosis doesn't necessarily include muscle issues".