The plantar fascia  is the flat band of tissue (ligament) that connects your heel bone to your toes. It supports the arch of your foot. If you strain your plantar fascia, it gets weak, swollen, and irritated (inflamed). Then your heel or the bottom of your foot hurts when you stand or walk.

Plantar fasciitis is common in middle-aged people. It also occurs in younger people who are on their feet a lot, like athletes or soldiers. It can happen in one foot or both feet.

Plantar fasciitis is caused by straining the ligament that supports your arch. Repeated strain can cause tiny tears in the ligament. These can lead to pain and swelling. This is more likely to happen if:

  • Your feet roll inward too much when you walk (excessive pronation ).
  • You have high arches or flat feet.
  • You walk, stand, or run for long periods of time, especially on hard surfaces.
  • You are overweight.
  • You wear shoes that don't fit well or are worn out.
  • You have tight Achilles tendons or calf muscles.