Supination is a turning outward of the foot at the ankle(Supination is the opposite of pronation), so that one has a tendency to walk on the lateral aspect (outside) of the foot.
You can recognize supination by looking at the back of the leg and foot. In a neutral or normal foot you can see the Achilles tendon run straight down the leg into the heel. If the foot is supinated, the tendon will run straight down the leg, but when it lies on the heel it will twist inward. This makes the outside of the ankle bone appear more prominent than the inside of the ankle bone.
Because supination is a twisting of the foot, all of the muscles and tendons which run from the leg and ankle into the foot will be twisted. If left untreated, supination may be the cause of heel spurs, plantar fasciitis, hallux limitus and rigidus, pain in the ball of the foot (metatarsalgia), shin splints, high and painful arches, and eventually knee, hip, and lower back pain.
To treat any symptoms or pain that may be caused by supination a patient must be cautious of the shoes that are worn and consider orthotics to control excessive supination. Old or worn shoes can actually increase the amount of supination on the patient. Wear an over the counter orthotic that will limit or correct the amount of supination (see The Ultimate orthotic). Stretching the calf muscles on a regular basis will benefit a patient and help reduce symptoms