"Back to that barefoot trail runner I mentioned earlier. We were running a 5K trail race at a similar pace. Every time the course opened up to a field, he was way ahead of me, and then back in the woods, he slowed considerably and I caught up with him. So I figured that I would pass him in the woods. And I did, while he carefully placed his bare feet on the uneven trail, I roared ahead. Until I caught my foot on a root and landed directly on my knee. Barefoot Man politely asked if I was ok as he glided past. Was it my unnatural, un-sensing shoes that caught on that root, or am I just uncoordinated? I'm not sure, but he crossed the finish a minute ahead of me and my bloody knee."
Shoes cause all sorts of injuries that we don't think of as being caused by shoes. Sprained ankles are another one, as are blisters.