The other day I slipped walking down the stairs while carrying something. I sort of tweaked my knee a bit, and so it felt somewhat weak thereafter.
After a couple days, my knee still felt weak. Then, I noticed my young son doing some "calf raises" (raising up on your toes). He does them periodically, and they aren't done for any specific purpose (like to reach something high). I'm assuming this is a built-in behavior which probably helps eventually develop the arch muscles.
I figured, what the heck, I would try them too. So the last few days, I did a quick set of 20 calf raises in the morning. Almost instantly, my knee felt better. Now this could have been a coincidence, but my other knee actually felt stronger as well!
I wonder if this kind of "Paleo" physical therapy, consisting of simple, natural movements, is on the horizon. I know there are people out there doing similar things already, but I wonder if this could the next branch of the overall Paleo movement.