colmike wrote: forget all that stuff about ankle support.
My experience with all this, limited though it is, is a bit different. I have a dodgy right ankle from a pretty rough ligament tear, several years old. It means when I lift my knee up, instead of hanging in a generally well aligned fashion like my left, my right foot hangs with the outside very low.
It’s not hard to imagine that causes problems stomping around rocky features in the middle of the night with heavy loads on my back. It’s an ankle that wants to roll at the best of times. So for me the value of a boot isn’t support, in any sense of it strengthening the joint, it’s value is in alignment. It keeps that wonky foot aligned so the natural ‘strength’ of the joint (as mike rightly points out) can do the work.
Obviously my case is extreme because of my goofy stump, but the aid in alignment is applicable to smaller degrees with other factors, like fatigue, steep inclines, rough terrain. Put weight on your back and all your tolerances narrow even further and the amount of damage done by a roll is enhanced.
All that being said I’ve met aborigines who’ve never worn a pair of shoes, I have a friend who runs several marathons a year barefoot. But they have the most hideous, gnarly feet I’ve ever seen 😉