Since we have a disease, I expect that the disease process sometimes carries on and any activity management that we do is moot.
Do you, however, have evidence for this.
In what proportion of patients are severe crashes (post initial period) correlated with unusual activity, and which aren't.
There is currently no evidence on this.
Both would be enormously valuable to patients.
Few people care that much about PEM lasting 4 or 5 days - if it can be avoided most of the time by modulating activity.
In comparison at least to if activity can trigger months or years of (worsened) disability.
If 'just got worse with no real reason' is vastly more common - then perhaps doing a bit more on average may be worthwhile.
If 'overdid it leading to crash' is - then research into better activity management.
The comment I made initially 'solidly psych' - was strong and incorrect - the final treatment may in some people involve development of coping strategies to work out your limits, even when you have cognitive problems leading to problems determining those limits. What I was actually meaning is there is value in principle in studies which do activity tracking and 'how are you feeling now' - with no 'biomedical' interventions (like the above study) but this wasn't clear.
There are reasonable mechanisms for 'just got worse randomly' - for example reinfection with some virus or other agent that triggers an echo of the original cause of CFS/ME.
And for 'was worse for 6 months after overdoing it' - just the 'normal' disease.
We have no way of knowing which is the case (or if both are). Any current data is terrible on this - any activity trials never follow up people who have withdrawn from the trial due to being unable to comply with the activity. Self selected surveys are equally problematic for many reasons.