Foot types can be divided into three major groups: the flat foot (Pes Planus), the high arched foot (Pes Valgus) and the normal to low arched foot. A true ‘flat foot’ is very rare. In fact, less than 5% of the population have flat feet i.e. a foot with no arch present whatsoever and the entire bottom surface of the foot being flat on the ground. About 5-10% of people have a high arched foot. The majority of the population have a normal to low arch. Even though the arches appear to be normal most of us suffer from over-pronation during walking, running and standing, due to the hard, flat unnatural surfaces we walk on, combined with wearing unsupportive footwear. With every step we take the arches flatten and the ankles roll inwards. Pronation itself is not wrong because we need to pronate and supinate as part of our natural gait cycle. Pronation (rolling in) acts as a shock-absorbing mechanism and supination (rolling out) helps to propel our feet forward. Over-pronation occurs when the foot pronates too deep and for too long, not allowing the foot to ‘recover’ and supinate. Over-pronation hampers our natural walking pattern. It causes an imbalance and leads to wear and tear in several parts of the body with every step we take.
Overpronation often occurs in people with flat feet, whose plantar fascia ligament is too flexible or too long, and therefore unable to properly support the longitudinal arch of the foot. People tend to inherit the foot structure that leads to overpronation. In a normal foot the bones are arranged so that two arches are formed, the longitudinal and the transverse. Ligaments hold all the bones in their correct positions, and tendons attach muscles to bones. If the bones are held together too loosely, they will tend to move inwards as this is the easiest direction for them to go. Over time the soft tissue structures will adjust to the misalignment and the foot will become permanently over-flexible, with a flat arch.
Not all foot injuries affecting runners are necessarily down to a particular running gait; it is rarely that simple to diagnose how a foot problem developed . Simply being an overpronator does not mean that a foot injury has been caused by the running gait and it could be due to a number of factors. However mild to severe overpronators tend to be at a higher risk of developing musculoskeletal problems due to the increased stresses and strains which are placed on the body when the foot does not move in an optimum manner. The following injuries are frequently due to overpronation of the feet. Tarsal tunnel syndrome. Shin splints. Anterior compartment syndrome. Plantar fasciitis. Achilles tendonitis. Bunions. Sesamoiditis. Stress fractures. Back and hip pain. Ankle pain.
A quick way to see if you over-pronate is to look for these signs. While standing straight with bare feet on the floor, look so see if the inside of your arch or sole touches the floor. Take a look at your hiking or running shoes; look for wear on the inside of the sole. Wet your feet and walk on a surface that will show the foot mark. If you have a neutral foot you should see your heel connected to the ball of your foot by a mark roughly half of width of your sole. If you over-pronate you will see greater than half and up to the full width of your sole.
Non Surgical Treatment
Adequate footwear can often help with conditions related to flat feet and high arches. Certified Pedorthists recommend selecting shoes featuring heel counters that make the heel of the shoe stronger to help resist or reduce excessive rearfoot motions. The heel counter is the hard piece in the back of the shoe that controls the foot?s motion from side-to-side. You can quickly test the effectiveness of a shoe?s heel counter by placing the shoe in the palm of your hand and putting your thumb in the mid-portion of the heel, trying to bend the back of the shoe. A heel counter that does not bend very much will provide superior motion control. Appropriate midsole density, the firmer the density, the more it will resist motion (important for a foot that overpronates or is pes planus), and the softer the density, the more it will shock absorb (important for a cavus foot with poor shock absorption) Wide base of support through the midfoot, to provide more support under a foot that is overpronated or the middle of the foot is collapsed inward.
With every step we take, we place at least half of our body weight on each foot (as we walk faster, or run, we can exert more than twice our body weight on each foot). As this amount of weight is applied to each foot there is a significant shock passed on to our body. Custom-made orthotics will absorb some of this shock, helping to protect our feet, ankles, knees, hips, and lower back.