What are the causes of plantar fasciitis? The plantar fascia, which is a bowstring shaped support of the arch, functions to absorb the stress and shock of our feet with activity. With excess tension and stress on the plantar fascia, the tissue is damaged and small tears can occur. The repetitive stretching and micro tearing of the fascia results in irritation or inflammation, which in turn causes heel pain while plantar fasciitis can occur without any identifiable cause. There are some factors which may increase the risk of developing plantar heel pain. And those include the start of a new or increased activity, repetitive impact activities such as running, a rigid high arched foot structure, a flat foot structure or excessive pronation, tight calf muscles, occupations where long periods of weightbearing activity are common, such as factory workers, teachers, or healthcare workers, and obesity, which is a contributing factor in approximately 70% of cases.