Is it true that the recovery speed depends on the size of the muscle? So for example large muscle such as legs need almost a week to recover while the small ones like forearms can be trained every other day ? (or more often in general)
That’s true, although I think a week is excessive. Look at Dr. Squats Training Split article. He explores this in great detail.
Look for the ABC training articles for how to put it in practice.
A week seems like a lot of recovery. However, when I was following Mike Mentzer’s HIT, he advocated 4-7 days between workouts to prevent over training. The only thing it prevented was me from progressing.
Forearms and calves can be worked more because of the muscle type (I remember reading this somewhere, so please don’t quote me). They have similar characteristics to that of your heart. Your heart is a muscle, very strong, but doesn’t increase in size.
actually your heart does increase. but much, much slower than any other muscle.its already almost at its plateau hence why its hard to make it bigger. as for the calves thats what you use for walking