(No, google didn't help. At least not in getting a definitive answer)
If I understood correctly, type II can't change into type I, and viceversa, and the differences found in, say, sprinters vs. marathoners are not that much due to variation in number of fibres (of course, a good sprinter has to be born with more type II's, a good marathoner has to be born with more type I's)...
...but due to the relative area of each fibre type (i.e. a sprinter has only developed his type II's, a marathoner has exclusively developed his type I's; so one can say that regardless of number of type I or II fibres one had, the type he didn't train atrophied, the one he did hypertrophied, and as such the relative areas are much lower/greater than in an untrained person).
Or, can type II's actually turn into type I's?
Asking because I had the revelation (yeah, maybe a year since reading 5/3/1) that doing some high rep sets might actually NOT reduce/hinder strength development, and be good for the joints. (hmm...if fibres don't change type, then developing type I's is actually very useful for PLing, right?)
Thank you for reading the wall of text,