Foot and Shoe Assessment

The foot is an incredibly complex mechanism, This introduction to the anatomy of the foot will not be exhaustive, but rather try and highlight the structures that will be of significant importance when making a choice in shoes.

1. Foot Physiology 101

The foot consists of three parts: the forefoot, midfoot and hindfoot.

The forefoot contains the five metatarsal bones and the phalanges of the toes. The first metatarsal bone belongs to the big toe, bears the most weight and thus plays the most important role in propulsion. It is the shortest and thickest providing anchorage for several tendons. The second, third, and fourth metatarsal bones are the most stable of the metatarsals.

Near the head of the first metatarsal, on the plantar (sole) surface of the foot, are two sesamoid bones. These are small, oval shaped bones that develop within a tendon where it passes over a bony prominence. They are held in place by the tendons and are supported by ligaments. They may occasionally be found on the fifth metatarsal bone (little toe).

The midfoot is made up of 5 rather irregular shaped bones; the navicular, cuboid, and three cuneiform bones, which link the hind- and forefoot. Together with the talus and calcaneum of the hindfoot, the make up the tarsus - the main weight bearing region of the foot. The calcaneus is the largest tarsal bone and forms the heel itself. The talus rests on top of it and forms the pivot of the ankle.

The foot rests on three points of support; posteriorly (at the back) on the calcaneus (heel) and in front, on the heads of the first and fifth metatarsal bones (big toe and little toe metatarsals).

The instep ("arch") is important in movement, acting as a spring. With weight on the foot, the arch in the foot is decreased, spreading weight towards the points of support. The arch "springs back" once the pressure has ceased. In this way it diminishes the jolting motion of walking resulting in a smooth, elastic movement. Tendons and muscles support the arch.

The toes, particularly the big toe, aid in balance and stability. In addition, when the heel is raised and the body weight is shifted on to the forefoot, the ends of the third phalanges (middle toe) are made to rest on the floor, increasing the surface area and thus distributing the transferred weight evenly.

2. Criteria for Good Shoes

Before one can buy a shoe, one has to know what criteria have to be met before shoe a can be deemed as valuable. The following are fundamental criteria that every athletic shoe should have:

• Stability - Shoes should be constructed in such a way as to prevent excessive or abnormal motion of the foot and leg.
• Durability - Shoes are extremely stable when new. Certain shoes break down more rapidly than others, losing their ability to resist abnormal forces. Therefore the shoe you select should be able to handle extended periods of strenuous exercise without visible deterioration.
• Availability - The desired shoe has to be readily available, having various distributors countrywide.
• Price Point - A trade-off should be reached between quality and pricing. Always remember that pricing does not necessarily reflect superiority.
• Quality Control - Certain shoes are extremely consistent in their manufacture thus the performance of that shoe is therefore predictable when recommended. In this regard, experience and word of mouth plays a big role. Please note that both are very subjective and therefore very arguable.
• Orthotic Compatibility - Since most shoes utilise functional orthotics as part of their "lower extremity injury plan", select the one that is suited to your feet and your biomechanical needs i.e. neutral, stability, motion-control.
• Special Features - While the aforementioned criteria are applicable to virtually every shoe, other shoe requirements might be vital i.e. an amphibious shoe that is quick drying and provides excellent grip on slippery surfaces.

3. Shoe Definitions

The following terminology is used exclusively in the shoe industry:

• Last - The template or mould around which the shoe is built. Different manufacturers use different lasts.
• Outer Sole - The outermost part of the sole that is treaded. On running shoes, the tread is designed for straight-ahead motion. Court shoes and cross trainers have their tread optimized for lateral or side-to-side stability.
• Upper - This part of the shoe encompasses the foot and contains the laces.
• Midsole - The portion between the upper and the outer-sole. This is the area where the major contribution to the shoe is shock absorption. It is also usually quite important that the midsole should be stable from the heel to the distal third of the shoe and from here to the tip it should be flexible in order for the foot to bend.
  EVA (Ethylene Vynil Acetate) is the most commonly used midsole material. It is heated and compressed into the shape of the midsole. It's light, resilient and has good cushioning.
• Sockliner - The liner inside the shoe that has a bit of an arch and usually some shock absorbing material incorporated into it.
• Heel counter - A rigid piece of material surrounding the heel in order to provide support and stability as well as controlling rearfoot motion.

4. Trying and Evaluating Different Shoes

If you have had no problems in running or racing, it is unnecessary to recommend a change in shoe. However, whether you are dissatisfied in general or are suffering from an injury as a result of an uneducated footwear decision, it's time for a change.

 Old Shoes Revisited

Examine the soles of your old shoes and note where wear has occurred.

Most people walk and run with the feet slightly rotated from the centre. Runners, however, also have what is called a narrow base of gait. Thus, when their feet make contact with the ground, the "width" between their feet is close relative to the midline of their body. This in turn, creates additional varus (tilting in) of the limb. For the rearfoot striker, the outer rear corner of their shoe will be the first point hitting the ground and thus the likeliest point to experience wear.

Forefoot wear often indicates an individual who is either a sprinter, runs fast, contacts the ground with the forefoot first, or all of the above.

Uneven forefoot wear may show where one metatarsal bone is plantarflexed relative to the others or where one metatarsal bone may be abnormally long. Those with forefoot wear are at risk of serious stress fractures.

Next, put your shoes on the table and look from the back of the shoe at the heel. If your shoe is tilted or bulging over to the inner part of the shoe, you may be an excessive pronator i.e. your feet that roll too far inwards when they hit the ground, especially found those with flat feet. You will also notice wear on the rear outer corner of your shoe. Should this be the case, look for a shoe that provides more stability or replace your shoes more frequently to benefit from their support.

If, however, your shoe tilts to the outside, you may have a high arched foot. In some cases, this can lead to ankle sprains as well as increased transmission of forces to the leg and back. Sometimes individuals with this type of foot may experience lateral knee pain, lower back pain and outer leg pain. For a high arched foot, considerable shock absorption and a less controlling shoe is crucial.

Types of Manufactured Shoes

Nearly all running shoe and trail-shoe manufacturers make shoes that are specifically designed for these three foot types. They are generally labelled as follows:

• Cushion (for high arches): These shoes come with extra cushioning in the midsole to help feet absorb shocks. Their soles are flexible and have a curved shape that promotes foot motion.
• Motion control (for flat feet): With a straight shape and a more rigid midsole than other running shoes, these reduce the degree of pronation and keep your feet properly aligned.
• Stability (for normal feet): These shoes also have a semi-curved shape with less rigid midsole's, which allow your feet to strike the ground naturally. Those with normal feet and normal weight are usually biomechanically efficient.

How To Make Sure Your Shoes Fit Properly

When deciding to buy a shoe for adventure racing, or running for that matter, a reputable store with a knowledgeable staff should be visited as far as possible. Unfortunately, in South Africa, a regular bloke with no 'shoe education' is used to help you fit a shoe - providing no expert opinion and giving you little help in making an informed decision.

The following list can either be used to test the impeccable knowledge of the sales staff or be used a guide on deciding which shoe to buy:

• Never focus on numerical sizes, since they vary a lot from brand to brand and from running shoe to dress shoes.
• Look for a snugly fitting heel; if it slips up and down when you run, you'll end up with blisters.
• The front of the shoe needs to be roomy. You should be able to wiggle your toes. Too tight shoes might result in "black toe-nails" and "bunions".
• Make sure the part of the shoe that supports your arch is snug but not tight.
• If you use orthotic's (customized shoe inserts), take them with you and make sure the desired shoe is compatible with them.
• Take along the socks in which you will be racing.
• Shop around for shoes after you have completed the day's running as your foot will then be slightly more swollen.

It is generally considered that the average lifespan for a running shoe is 600 kilometres. However, the type of shoe, the type of runner as well as the type of terrain covered will influence this statistic considerably.

5. If All Else Fails... Get the Experts

Alternatively, if you find the whole shopping-for-shoe expedition much too daunting, a second - more advisable - approach is available. The Sports Science Institute of South Africa can be contacted for a foot and shoe assessment. The once-off amount of R70-00 is well worth it.
They will recommend shoes that are most suited to your foot type and since they keep your records, when you are looking for your next pair you can just phone them and ask for a current shoe that will fit your profile.

Please contact us now - rsa@ndorfin.co.za