Plantar fasciitis is caused by strain to the plantar fascia under the foot. The cause could be degenerative or a previous injury. It can occur if you wear poor footwear, eg. shoes with thin soles or shoes without sufficient support. Other causes include:
- Returning to strenuous activity after a long period of rest
- Having a short calf muscle
- Having poor ankle range of motion
Middle-aged people are most commonly affected.