The only overuse injury I've ever had was shin splints back when I was running 10 miles a day. I tend to back off at the first sign of trouble with tendons or knees. I also back off when I'm not pretty much fully recovered by the next day except for normal morning soreness in muscles that disappears quickly when I exercise again. This would probably make me a lousy thru-hiker as I'm thru-hiking before most who do this.

My observation is tendon injuries and knee problems tend to become chronic once people have them, so I do everything I can to avoid them. Maybe my approach is right or maybe I've just been lucky.

OM, it's not surprising your son had problems in AF boots. They are made for a different purpose than those made for the Army and Marines. Even in the Army and Marines, boots are now specific to the use. My theory may be busted on the high top, except I've noticed the minor onset of issues with lower top boots. (Mountain Lites) One thing I do like about combat boots is you can find a lot of reviews from people who used them until they were worn out. Initial feelings of comfort in shoes may be misleading. I get the feeling there is more research done about what colors and looks will sell than there is on how good they are for the feet.

Gotta run. It's time to get ready for an overnight trip.