What is Plantar Fasciitis? Plantar fasciitis is a painful condition caused by a stretching of the tendon on the bottom of the foot called the plantar fascia.  Icing and stretching will only provide temporary relief to the pain while insoles provide long term pain relief. This is because the best insoles for plantar fasciitis provide very specific correction for your heel, arches and forefoot, provide cushion for your feet and reduce the pull on the plantar fascial tendon. Treat What Causes...