Supination and Pronation Explained

Supination and pronation are terms used to describe the rolling motion of the feet, and are processes which occur during a natural walking gait. Foot pronation is used to describe the inward rolling of the foot, and foot supination is used to describe the outward rolling of the foot. Both happen to some degree during the stride.

Whilst pronation and supination are fine, if you have excessive inward rolling of the foot - termed overpronation - or the opposite which is outward rolling or inflexibility in the feet - often termed under pronation or over supination - it is not so good, as both can place an unhealthy strain on the feet.

Under or over pronating becomes more of a problem when running due to the increased forces acting on the feet when moving at speed. In both cases, it can lead to pain in the feet, but also pain throughout the whole of the lower body. In mild cases it may just be a case of hard skin, corns and calluses forming on the feet at pressure points. In cases where the rolling is excessive, it can lead to joint pain in the ankles, knees and hips, as well as contributing to shin splints and increasing the chances of muscle sprains.

Overpronation is the term used to describe an excessive rolling of the foot from the outside of the heel, to the inside of the foot when running. Whilst this happens naturally to a degree, overpronation is when the foot rolls more than 15 degree inwards from the ankle.

Overpronators have a pronounced side to side movement of the feet when running, which can place an increased strain on the big toe and the ball of the foot. They have a tendency to push off on the inside edge of the foot at the push off, rather than an even force across the whole of the ball of the foot from a normal running gait.

Overpronators tend to wear out shoes on the outside of the heel, and on the inside of the forefoot much faster, due to the increased forces acting on both of these areas. If you check an old pair of running shoes, if you overpronate, these areas will show a significant increase in wear.

Underpronation or Supination is the opposite of pronation, and is often termed underpronation due to there being a lack of sufficient rolling inwards of the feet. Underpronators, or supinators have little bend in the lower leg, and when the heel strikes, the weight stays on the outside edge of the foot, with the push off coming from the little toe.

Supinators tend not to be able to cushion the shock waves from running well. with the foot arches unable to deal effectively with the forces from running due to the irregular gait. Supinators tend to wear out their shoes on the outside edge much faster, with old running shoes becoming worn all along the outside edge.

Overpronation and underpronation can be assessed with a quick home test to check your foot arches, as it is the shape of your feet which often leads to both of these gait irregularities. 

Its quite easy to check your feet to see if you have high, low or normal arches. It is difficult to identify your arch type simply by looking at your feet, and the best way to check is by looking at your footprints.

To check your arches, you need to fill a shallow dish with water and get your feet wet. Then step onto absorbent paper and the moisture will leave an impression of the underside of your feet.

Normal foot arches will show the ball of the foot and the heel connected by a medium sized band. If you have flat feet, or low foot arches, there will be next to no narrowing between the ball of the foot and the heel, and it is likely that you will be prone to overpronate when walking and running.

If you have high arches, the band connecting the ball of the foot with the heel will be very narrow, and this indicates that you may under pronate when walking. When this is the case, your feet will not be able to deal effectively with the shock waves from walking and you will need increased support and cushioning to make up for poor foot function.

Check the diagram below for a guide to your foot prints to see which category your feet fall into. Low arches and overpronating feet are far more common than high arches and under-pronating feet.

Unfortunately, you cannot change your foot arches and you are stuck with the shape of your feet. However if you are prone to over pronate, or under pronate there are some simple steps you can take to biomechanically correct your stride.

Making a change is important, as it will ensure that your feet move in a much healthier fashion, and will reduce the strain on your feet and lower legs. In cases of excessive supination and pronation it may be necessary to have custom orthotic insoles made to give you the maximum level of support; however in the vast majority of cases this is prohibitively expensive and not always necessary. Factory orthotic insoles are a much more cost effective solution, and in most cases are sufficient.

The top running shoes manufacturers all offering running sneakers which can help to correct the various degrees of supination and pronation, with Brooks, Asics and Mizuno offering the greatest range.

If you have high foot arches, underpronate or have supinating feet the best bet is to choose footwear with the maximum amount of cushioning, and avoid barefoot shoes, as these will make the problem considerably worse. Neutral running shoes are best, and lightweight models a good choice as these help to increase the flexibility in the foot and lower leg.

Orthotic insoles can be beneficial to give increased support for both high and low arches, and they help to biomechanically correct the stride, whilst providing increased support and cushioning. Orthotic insoles can be fitted into virtually all shoe types, with many manufacturers offer a trim to fit design and a wide range of styles to suit narrower shoes and sports shoes, as well as standard width footwear. In most cases, it is best to use them with footwear which features a removable insole, as this will make the fit more comfortable and will not make your shoes too tight.

It is always best to purchase orthotic insoles from a big name brand, as they provide a superior quality of construction which will protect and support your feet for longer. In most cases you can expect to get up to 12 months of use before they need to be replaced. Whilst cheaper models are widespread, you will find that spending a little more will mean that you have to replace them far less frequently, which will ensure greater value for money in the long run.

Some of the best brands include Superfeet, Sorbothane, Sole, Orthaheel (Dr. Scholls) Sof Sole, Aetrex, Lynco and Spenco.

All of these brands offer a wide choice, so check the individual model to ensure that it is suitable for your main activity and gives the level of support that your feet require. Just as with shoes, there are male and female models which offer support to the differing anatomies of men's and women's feet, and be sure to chose the range which fits your specific shoe size.

Sole insoles deserve a special mention as they offer more of a custom fit than most standard insoles and shoe inserts. For the best fit, Sole insoles can be heated gently in the oven to soften them up, and then slipped into your shoes. They will then instantly take on the shape of your feet, and as they cool will retain that shape, although if you don't have an oven you can slip them in your shoes and over a few days they will take on the shape of your feet.

High foot arches are often associated with excessive supination or under pronation as it is often called. When the arches are high, foot function is impaired as the feet cannot roll as effectively when walking. High arched feet are unable to deal effectively with the shocks and strains from walking, and cannot pronate properly. When the feet cannot pronate properly, they require additional cushioning to make up for the lack of movement, and to help correct an outward roll.

Custom orthotics are costly, as they require a mould to be taken of your feet, from which a custom orthotic support is then made. They undoubtedly offer the greatest support to the feet, and they are tailor made for a highly individual fit to provide maximum support and stride correction. Your podiatrist will be best placed to advise you if a custom orthotic is required, or if factory orthotics will be sufficient.