Since my arches collpased a couple years ago from years of pronating and running without orthotics, I can tell that my knees seem to take more of the brunt of the impact. I can especially tell when running on concrete. Some other running I talk to with flat feet tend to think otherwise. Anyone here have total flat feet, I mean no arches at all? Did you try anything to try to strengthen your arches other than orthotics which do absolutely nothing other than preventing the arch from completely bottoming out when you pronate.