More on the Harvard study:
The study DOES have some useful info for the heel striker and flat footed person. If you run, try leaning slightly forward to move the weight forward on your foot. Try not to land on the heel, but rather, flat footed or in the middle of your foot. You can do this in your regular pair of running shoes. It is good to absorb some shock in the foot, because it “spreads the wealth” if you will- it gives the body more joints & muscles to absorb force with.
For flat-footers who have foot pain & are looking to improve their arches, walk around barefoot as much as possible at home. But if your feet start to hurt, by gosh, put on shoes!!! It takes time to strengthen up those arches. FYI- flat footers are notorious for weak calf muscles- so try some barefoot calf raises every day to strengthen your calf muscles & help re-create an arch. You should be able to raise your heel 20x in a row (no rest) when standing on one leg- Try for a couple sets of these each day. Go up as high as you can with each rep. If daily calf raises cause foot pain, you may be strengthening too aggressively.