In this blog Cypress Foot and Ankle expert Dr. Christopher Correa discusses what the terms Pronation and Supination mean. The foot and ankle is a complex mechanical system that facilitates locomotion and attempts to accomplish two minor goals during this process, energy redirection and shock absorption. This first task is achieved through the coordinated storage and release of kinetic forces which serves to optimize locomotion with minimizing energy expenditure. The foot needs to at times be flexible and flatten (pronate) early in the gait cycle to absorb shock and allow for the storage of elastic energy in the ligaments for later discharge. Energy storage is achieved through elastic loading of the soft tissues such as the plantar ligaments and tendons. As the body moves forward on a planted foot this elastic energy is discharged which helps resupinate the foot (increase arch height) making the foot stiff and rigid allowing it to act as a more effective lever to push off from. These motions of the foot and ankle are coupled together and actually occur in all three cardinal planes of motion simultaneously. These two separate groupings of motions known as supination and pronation.
What is Supination?
Supination describes the motion which increases the arch height and shifts the body weight toward the outside of the foot. This upward and external rotation of the hind foot (when standing) serves to lock the mid foot joints creating a stiff foot. This is useful during gait at the end of stance phase where the foot needs to be relatively rigid in order to push off from. Supinated feet are ones with high arches with most of the weight passing along the outer edge of the foot.
What is Pronation?
Conversely pronation is where the arch lowers and the hind foot internally rotates (when standing). When the foot is pronated this unlocks the mid tarsal joints allowing for flexion and extension through the mid tarsal joint. The motion afforded with pronating during stance phase allows for the foot to dissipate energy and reduce stress and strain experienced at any particular joints in the mid foot. Additionally, this lowering of the arch stretches the plantar supporting structures elastically charging them. As the gait cycle continues this energy is then used to assist in re-supination towards the end of the stance phase.
Bottom line, pronated feet are flatfeet. Let’s see how these two motions play out in action.
Pronation, Supination and Foot Function during the Gait Cycle
The interplay of the foot with the ground begins when the heel strikes the ground with the foot in a supinated or high arched position. This keeps the foot stiff as it rolls over the heel bone. Once the foot is flat on the ground it begins to pronate or flatten. This flattening serves to unlock the mid foot joints and allow for elastic stretching of the plantar supporting ligaments. This flexibility of the mid foot also dissipates the forces of ambulation across the foot dampening them and protecting the boney structure preventing premature wear and tear in the mid foot. Once the body has passed over the foot the heel raises off of the ground and the foot begins to re-supinate to a high arched position. This is assisted by the previously elastically charged ligaments which now contract passively raising the arch. The re-supination pushes the foot into a higher arched and rigid structure which is used as a rigid level the body pushes off from propelling the person forward.
While the average person typically has heard of pronation, they usually have heard of it in the form of “pronation syndrome” or some sort of supposed pathological process. Pronation syndrome is a non-specific term referring to a variety of reasons why the foot stays in a pronated position and fails to resupinate during gait. Conversely there are high arched feet out there that fail to pronate enough during gait leading to a whole host of their own problems and yet we do not call it supination syndrome. Improper posture during gait can lead to problems such as neuromas, plantar fasciitis, arthritis, bunions and more. Take home point, there is a number of reasons as to why a foot may be flat or high arched. The terms supination and pronation are normal motions that simply represent two sides of the same coin. There are a variety of reasons why a foot might do too much of one and not enough of the other and these are hashed out on an individual basis. With a complex array of things that may be affecting the gait cycle a trained professional can take all of these factors into account and narrow down the underlying cause of your foot or ankle pain. For some orthotics could provide relief from the symptoms of flat achy tired feet. If you are experiencing foot or ankle pain, call the experts at Select Foot and Ankle Specialists and take the first step towards recovery today!