Plantar fasciitis is a painful inflammation of the plantar fascia, a fibrous band of tissue on the bottom of the foot that helps to support the arch. Plantar fasciitis occurs when this band of tissue is overloaded or overstretched. This causes small tears in the fibers of the fascia, especially where the fascia meets the heel bone.
Plantar fasciitis is common in obese people and in pregnant women, perhaps because their extra body weight overloads the delicate plantar fascia. It is also more common in people with diabetes, although the exact reason for this is unknown.
Plantar fasciitis also can be triggered by physical activities that overstretch the fascia, including sports (volleyball, running, tennis), other exercises (step aerobics, stair climbing) or household exertion (pushing furniture or a large appliance). In athletes, plantar fasciitis may follow intense training, especially in runners who push themselves too quickly to run longer distances.
Worn or poorly constructed shoes can contribute to the problem if they do not provide enough arch support, heel cushion or sole flexibility.