Supination is a natural anatomical movement that is necessary to occur during both walking and running which helps to provide adequate leverage to the foot.
When standing, supination occurs as the foot rolls outwards, placing most of the weight onto the outside of the foot and raising the arch. Supination is a normal part of the gait cycle (walking/running) which allows the foot to form a rigid structure for propulsion.
Supination can be subdivided into 3 separate body movements occurring in 3 separate body planes, defined as :-
ADDUCTION PLANTARFLEXION INVERSION
How Can I Tell if I Over supinate ?
Firstly, look at your feet when standing. Is there a high arch on the inside of the foot ?
Secondly, look at your running shoes. If they are worn on the outside of the sole, especially on the forefoot area, then supination may be excessive when you run.
Thirdly, try the wet foot test.
A normal foot will leave a print of the heel, connected to the forefoot by a strip approximately half the width of the foot on the outside of the sole. If your feet are supinated the print of the heel and the forefoot will be connected by only a thin strip on the outside, or may not even be connected.
Wet Foot Test
How Does This Cause Injury?
Over supination usually causes over-use type injuries, occurring most frequently in runners. A foot which over-supinate’s, under-pronates. Pronation allows the foot to absorb shock and mould to the surface of the ground. Therefore in over-supinated feet, shock absorption is reduced. The stresses normally absorbed by the foot are then passed up the lower limb.
Over-supination also causes an increased external (lateral) rotation force to be placed on the shin, knee and thigh which places additional stress on the muscles, tendons and ligaments of the lower limb.
Over supination is less common than over pronation and causes problems for runners and other athletes, as in this position the foot is less able to provide shock absorption. It therefore predisposes the athlete to:-
- Shin splints
- Plantar fasciitis
- Ankle sprains
- Stress fractures of the tibia, calcaneus and metatarsals