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Pronation and Supination are common terms that are often associated with fallen arches, high arches, flat feet etc. This article discusses the significance of these terms and enumerates the particular problem of over-pronation. This is what you will learn from the article:
1) What the terms Pronation and Supination denote
2) What is meant by over-pronation in the broad sense
3) What are the consequences of over-pronation
4) What can be done to treat over-pronation
"Pronation" and "Supination" are terms one needs to understand by considering the "gait" or walking style or simply "the way we walk".
The "gait" constitutes three different phases:
1) Contact Phase: When the foot lands, the outside of the heel makes contact with the ground first. This is why generally the outside heel area of the shoe soles wear out faster than the rest of the shoe. After heel strike the foot flattens out and the ankle rolls inwards and this phenomenon is known as “pronation”. Simultaneously the knee and lower leg rotates inwards as well. The "pronation" effect makes your foot loose and flexible thereby taking up the shape of the ground contour. Pronation can also be understood as the natural shock absorbing mechanism of the walking cycle and the contact phase continues until the foot is firmly flat on the walking surface.
2) Midstance Phase: The foot comes flat on the ground while the body weight presses over your foot as you move forward. The gait emphasizes the fact that the foot is supporting your body's weight. Midstance phase accentuates problems for over-pronated (fallen arches) or over-supinated feet (high arched foot) in the gait cycle.
The phase ends when the body weight shifts forward by allowing your heels to lift from the ground. Supination (i.e. the opposite of pronation) takes place as the muscles tighten making the foot a rigid lever that pull the leg muscles. The foot becomes rigid it prepares itself to take off. Supination makes the foot roll outwards as the lower leg rotates externally.
3) Propulsion Phase: In this phase the forefoot pushes against the ground to propel the body forward. The body weight is supported by the ball of the foot followed by absorption of the weight by the big toe as you push your foot forward. It is important to understand that both pronation and supination are part of a normal and healthy walking pattern! Rolling inward or pronation acts as a shock absorber while supination or rolling outward aids in propelling our feet and body in a forward motion.
Exerting the foot beyond its capability results in over-pronation and it does not get a chance to recover or 'supinate'. The state of over-pronation uses excessive energy during walking thereby causing imbalance, strain on the feet, legs, knees, and lower back. Several terms are used for over-pronation. These are 'fallen arches', 'dropped arches', or 'collapsed arches'. Though the term "flat foot" is also used it could be a misnomer since a true flat foot is quite rare as hardly 5 percent of the population exhibit a true 'flat foot' (Pes Planus) without arches. Ninety percent of humans have normal to low arches while only 5 percent possess high arches. Pes Cavus or high arch is also known as over-supination where the foot stays rigid most of the time. It also lacks the natural shock absorbing mechanism.
It is important to appreciate that one does not have to be flat footed to suffer from the condition of over-pronation. On the other hand, many people with a 'normal- to-low arch' condition suffer from this ailment. Normal sitting posture does not accentuate the arches nor does standing upright shows a high degree of over-pronation. However, the moment one starts walking this condition manifests. With every step we take, the arches collapse and ankles roll inwards.
Over-pronation can be caused by several factors. Weak ankle muscles, obesity, pregnancy, age or forceful gait against hard ground can lead to over-pronation. Athletes, especially runners, are more prone to this condition.
If you are suffering from over-pronation (like 70% of the population) a variety of complaints may occur due to your poor walking posture. Young people under forty tend to suffer from over-pronation without any clear symptoms, aches or other complaints.
As people approach their forties or fifties the poor foot function gives way to over-pronation resulting in excessive wear and tear of the feet, ankle and knee joints as well as the lower back. Mostly people accept these changes as normal signs of ageing. Little do they realize that the signs could be due to the fallen arches!
Plantar Fasciitis is the most common condition caused by over-pronation. As the feet flatten, the fibrous band of ligaments under the feet (Plantar Fasciitis) becomes overly stretched. This results in inflammation at the point where the fascia attaches to the heel bone. Plantar Fasciitis causes chronic heel pain and sometimes a bony growth develops at the heel bone known as a heel spur.
As a result of over-pronation the foot continues to roll inwards when it really should be pushing off and outwards! When this occurs the lower leg also follows the internal rotation and stays in this position in place of supination or external rotation. This places a lot of strain on the leg muscles (especially the calf muscles) causing leg ache and shin splints. The twisting of the lower leg further displaces the knee cap or patella. The knee is a hinge joint that is designed to flex and extend like a door and not built to rotate! When the legs rotate inwards, the pelvis is forced to tilt forward. The end result is a constant strain or stress on the lower back muscles.
Although there is no real cure for over-pronation it is possible to take steps to prevent the discomfort. Orthotics inside the shoes are a boon to reducing the effect of over-pronation on the body.
In order to restore our normal foot function an 'orthotic' or orthotic insole device is placed inside the shoes. This is also called a shoe insert. Different types of foot orthotics are available in the market that can be purchased from pharmacies, reputable shoe stores and specialty websites. These can be custom devices as prescribed by a Podiatrist or ready made 'off the shelf' orthotics that some companies manufacture.
Orthotics are supposed to correct the problem of over-pronation as they realign the foot and ankle bones to their natural position. This in turn restores our normal foot function that alleviates not only foot problems but also ailments in other parts of the body.
In addition to wearing an Orthotic, it is recommended to wear supportive shoes with plenty of 'motion control'. These special shoes incorporate 'motion control' by placing arch support and firm heel counters to stabilize the heel and ankle during the walking cycle. They reduce over-pronation by also having side posts for extra lateral support. The firm midsoles further reduce pronation while protecting the ankles and knees from lateral stress. The inner side of the midsole may be made of a denser material (dual density midsoles) to reduce the amount of pronation. A heavy person who overpronates will need a heavier, more supportive shoe than a light person with the same degree of pronation.
These days the shoes use soft material for reasons of initial comfort and are not really supportive or stable for a healthy gait. The use of sandals or 'flip-flops' during summer is of no help to patients with over-pronation as they are not satisfactory in biomechanical terms.
Find out more about pronation, fallen arches, foot and heel pain and orthotics at www.painfreewalking.co.uk
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