I played with these when I got plantar fasciitis. They helped me manage it, the stiff arch support seemed to be effective in preventing the fasciitis from being continually reaggravated. However, oddly, once the fasciitis was healed, I had to quit using these insoles because they seemed to create new pain on the lateral side of my foot. I've never been able to understand why it wasn't an issue when the fascia was actually injured. edit: also, if you play with these in summer, i recommend covering the poron foam at the heel with a single layer of electrical tape, as hot and humid conditions cause the poron to disintegrate as it rubs against the interior shank