Biomechanical factors that contribute to plantar fasciitis include flat feet and high arches. A runner with heel pain is more likely to have flat feet and pronate. If you pronate excessively, the hind foot will have decreased stability, and this adds more strain on the plantar fascia at its heel attachment during the stance and push-off phase of running. In the runner with high arched feet, there will be decreased motion where the ankle attaches to the foot, and this results in decreased ability of the foot to absorb the force of ground contact. At foot strike, the heel remains rolled outward, and the longitudinal arch remains rigid throughout the midstance phase of running.
Stress is passed through the outer border of the foot and knee.
Factors which can be controlled include training progression, environmental factors, shoes, and strength and flexibility exercises. Terrain is also an important factor in training. Running 30 minutes on hills is very different from running 30 minutes on flat surfaces in terms of the forces on the legs and feet. Work up gradually to increase your running time on hills. Also lean forward when running downhill.