Supination is a normal part of the gait cycle and is an essential movement for activities such as walking and running. However, over-supination causes problems which leads to injuries. Supination occurs when the subtalar joint moves into inversion (turning the sole inwards), plantarflexion (pointing the toes away from you) and adduction (pointing the toes across your body). Supination is the movement when foot rolls outwards while standing. This places the majority of the weight onto the lateral side of the foot and raises the arch. Pronation is the opposite movement of supination. Pronation is also a normal part of the gait cycle. Excessive pronation is known as overpronation, which also leads to problems.
Oversupination is less common than overpronation. It commonly occurs in athletes such as runners. In this position, the foot is not able to provide proper shock absorption thus causing injury and pain.
Mechanism of Injury during Oversupination of Foot
Oversupination commonly leads to overuse type of injuries. Athletes such as runners are more commonly affected by this injury. Pronation is the movement due to which the foot is able to absorb shock and adjust itself on the ground. In case of oversupination of the feet, there is reduction in the shock absorption and this puts more stress on the lower limb which otherwise is absorbed by the foot. Oversupination also leads to increased external rotation force on the shin, knee and thigh. This in turn puts excessive stress on the muscles, tendons and ligaments of the lower limb causing pain.
Diagnosis of Oversupination of Foot
- Observe your feet when standing. If there is a higher than normal arch present, then this indicates oversupination.
- Observe your running shoes. If these are worn out on the outside region of the sole, in particular the forefoot area, then it means you over-supinate when running.
- Another way of finding out is the wet foot test. Soak your feet in water and walk a few steps. Observe your footprints. In case of a normal foot, the print of the heel is connected to the forefoot by a band which is about half the width of the foot on the outside part of the sole. In case of oversupination, the print of the heel and the forefoot is connected by a thin band on the outside, or sometimes may not be connected at all.
Treatment of Oversupination of Foot
- Getting a gait analysis done by podiatrists, physiotherapists or sports therapists of your running style helps in distinguishing between overpronation, oversupination and a neutral gait.
- In case of oversupination, running shoes which are extremely cushioned and flexible should be used. This helps in shock absorption at the foot.
- In severe cases of oversupination, orthotic devices can be fitted. Most of the times, patients can use the orthotic insoles that can be bought off the shelf, but some patients may require custom made orthotic devices which can be prescribed by a sports injury therapist or a podiatrist.