The Plantar Fasciae is a connective tissue on the sole of the foot which is responsible for the transference of load during the weight bearing phase of running. It does this via the Windlass Mechanism. If the foot fails to function normally biomechanically, or you have unstable or worn running shoes, or you have built up your running too quickly - the plantar fasciae can become inflamed.
Plantar fascitis is characterised by pain on the sole of the foot and is particularly tender first thing in the morning.
Research suggests that there also may be a neutral component to this problem. Calcaneal fat pad irritation is closely associated with plantar fascitis. It can be very painful and last for many months.
Physiotherapists should identify the cause of the problem and use hands on skills to release any of the structures around the foot responsible for creating the problem. They may use acupuncture to release tight muscles and relieve pain. They will teach you exercises to stretch and strengthen the foot and may tape it to support the tissues when you return to running.
If there is a structural problem they may refer you to a podiatrist for further analysis, it may be that it will require the use of orthotics to settle the problem.