The plantar fascia is very hard and tense, considering plantar fasciitis, calcium deficiency, trauma, lower extremity vascular disease and other reasons. 1. plantar fasciitis: due to walking or standing too much will cause chronic strain on the plantar fascia, localized edema, spasm. The plantar fascia is very hard and taut. 2. Calcium deficiency: When calcium deficiency occurs, muscle excitability increases, and the plantar muscles twitch and localize very hard. 3. Trauma: after fracture, ligament or soft tissue injury of the foot, local bleeding and oozing, edema, the tendon can appear very hard and taut. 4. Lower limb vascular disease: for example, diabetic vascular lesions, lower limb thrombotic occlusive vasculitis caused by insufficient blood supply to the lower limbs, local ischemia and hypoxia, causing muscle spasm. The cause of the plantar fascia is very hard and tense, there are a variety of possible causes, you need to go to the hospital to check the cause of the disease and then treatment.