Naturally, we are designed to walk barefoot, which allows the toes to grip the ground as we walk or 
run through gait. As the toes flex to grip the ground, the muscles that support the arch of the foot engage and strengthen. However, because we spend most of our time walking on hard, flat surfaces we wear footwear that pads and supports our feet but does not allow these muscles to engage.
What takes most of the load, if the musculature is weak? You guessed it, the plantar fascia. This thick, fibrous band becomes overload and small tears occur in the fascia. Scar tissue forms to repair the damage, further constricting the plantar fascia until tension and pain develops, typically at the inside arch toward the foot toward the heel. This condition typically responds well to Active Release Technique of the plantar fascia and calf, foot manipulation to restore mobility to the many joints of the foot, followed by strengthening exercises.