Plantar fasciitis is one of the most common causes of heel pain. It involves pain and inflammation of a thick band of tissue, called the plantar fascia, that runs across the bottom of your foot and connects your heel bone to your toes.
Plantar fasciitis commonly causes stabbing pain that usually occurs with your very first steps in the morning. Once your foot limbers up, the pain of plantar fasciitis normally decreases, but it may return after long periods of standing or after getting up from a seated position.
Plantar fasciitis is particularly common in runners. In addition, people who are overweight and those who wear shoes with inadequate support are at risk of plantar fasciitis.
Plantar fasciitis typically causes a stabbing pain in the bottom of your foot near the heel. The pain is usually worst with the first few steps after awakening, although it can also be triggered by long periods of standing or getting up from a seated position.
Under normal circumstances, your plantar fascia acts like a shock-absorbing bowstring, supporting the arch in your foot. If tension on that bowstring becomes too great, it can create small tears in the fascia. Repetitive stretching and tearing can cause the fascia to become irritated or inflamed.

Factors that may increase your risk of developing plantar fasciitis include:

Age. Plantar fasciitis is most common between the ages of 40 and 60.
Certain types of exercise. Activities that place a lot of stress on your heel and attached tissue — such as long-distance running, ballet dancing and dance aerobics — can contribute to an earlier onset of plantar fasciitis.
Faulty foot mechanics. Being flat-footed, having a high arch or even having an abnormal pattern of walking can adversely affect the way weight is distributed when you're standing and put added stress on the plantar fascia.
Obesity. Excess pounds put extra stress on your plantar fascia.
Occupations that keep you on your feet. Factory workers, teachers and others who spend most of their work hours walking or standing on hard surfaces can damage their plantar fascia.
Ignoring plantar fasciitis may result in chronic heel pain that hinders your regular activities. If you change the way you walk to minimize plantar fasciitis pain, you might also develop foot, knee, hip or back problems.