For the rating scale at the end of the work-out: None of the work-outs are.”very hard” for me in terms of skill level, and certainly not “extremely hard.” But this is what I have to choose if I want to rate my perceived effort as an 8 or 9. I suggest changing the language to accurately reflect what we are trying to measure, which is subjectively the amount of effort we feel we put into the work-out. When look back at my log book, that is what I want to see recorded, not whether or not I found the work-out itself difficult.