Plantar fasciitis is caused by structural problems within the foot. People with flat feet have an extra long plantar fascia. This creates a greater distance between the heel and the balls of the feet. Those with high arches have a short plantar fascia. And, people with short plantar fascia are more prone to plantar fasciitis. Sudden weight gain, obesity, and prolonged standing or walking on hard surfaces can all contribute to plantar fasciitis.