WHAT IS IT? Plantar fasciitis is one of the most common sources of heel pain, and is experienced by thousands of Australians at any given time. It is an irritation to the plantar fascia (the thick band of ligamentous tissue running along the sole of the foot), causing sharp pain, swelling and stiffness at the base of the heel. In most cases, this irritation is caused by overstretching of the fascia. Plantar fasciitis commonly presents with intense morning pain, and pain after