Plantar fasciitis occurs when the long, flat ligament on the bottom of the foot (plantar fascia) stretches irregularly and develops small tears that may cause the ligament to become inflamed. It causes heel pain, which can become long-lasting.

Plantar fasciitis is the result of repeated stress on the foot that may be caused by normal aging or being overweight. Other causes of plantar fasciitis include:

• Activities such as running and jumping, which increase weight and stress on the foot.
• Foot conditions, such as having high arches, flat feet, or tight calf muscles or heel tendons, or walking with an inward twist or roll of the foot (pronation).

The most common symptom of plantar fasciitis is sharp or knifelike heel pain that usually occurs when a person gets up in the morning and takes the first few steps. The pain also may occur when the person stands up after sitting for a period of time.

Home treatment, such as rest, ice, strengthening exercises, flexibility exercises, and orthotic devices, may relieve symptoms. A doctor may recommend medication, splints, surgery, or physical therapy.