What it is
A painful condition that occurs when the band of tissue along the bottom of the foot (plantar fascia) gets overstretched and becomes inflamed. A classic symptom: pain upon taking first steps of the day.
Why you get it
Bad biomechanics can stress the heel. Also can be caused by jumping and running a lot, and wearing shoes without arch support. People with flat feet are most at risk.
Treatment
Night splints, orthotics, non-steroidal anti-inflammatory medication, stretching, cortisone injections, casting, shoes with extra support, even shock-wave therapy.
Prevention
Wear shoes with proper arch support; ballet flats can stretch the plantar fascia, as can worn-out workout shoes.