What causes plantar fasciitis?

Jane Milliff
Physical Therapy Specialist

Plantar fasciitis is an inflammation and micro tearing of the ligament that supports the arch in your foot-- the plantar fascia. When your foot hits the ground, the plantar fascia stretches to accommodate your body weight and the ground reaction forces generated by walking and running. During walking, up to 3 times your body weight is taken through your arch; when running, up to 9 times. If the condition develops, the person usually reports a sharp pain under their heel that may spread into the arch of the foot. The onset is typically not from an injury, but develops gradually and, if left untreated, gets worse over time. Many causes can contribute to plantar fasciitis:

  • Standing on your feet all day with poor foot wear
  • Increasing running intensity or distance too quickly
  • Shoes inappropriate for your foot type or shoes that have excessive wear
  • Poor foot mechanics (foot is too flexible or too stiff)
  • Weakness in your core, hips, and lower leg
  • Tight legs, especially calves
  • Low back pathologies with nerve root irritation
  • Poor running mechanics

To get better, one must address the particular issues that precipitated the pain. Having cushioned and supportive shoes is a first step. 

Rick Olderman
Physical Therapy Specialist

The plantar fascia on the bottom of the foot becomes inflamed when overused or overly stressed. Most plantar fasciitis is due to a combination of overly stretching the plantar fascia and excessive loading of the fascia. There are several factors that play into this:

  1. the overall mobility of the foot into pronation or supination
  2. footstrike patterns
  3. the structural nature of the femurs (retroversion or anteversion)
  4. calf and soleus muscle length

A common cause of plantar fasciitis is over-pronation of the foot.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.