Rocky Mountain Runner

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The Definitive Guide to Running Shoes
by André Zapatos
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Is there a simpler sport than running? The only needed equipment is a good pair of running shoes. If only choosing a pair of running shoes were simple!

Ah, but it is--if you know what your needs are. So how does one determine their needs?

First, a few terms...

PRONATION
Pronation refers to the movement inward of your sub-talar joint (ankle) upon landing. Everybody pronates--hopefully! This is what allows your body to absorb the shock of your footfall. Four to six degrees of pronation is common and necessary for shock absorbtion.

OVERPRONATION
Overpronation refers to the act of pronating, or moving inward too much--more than six degrees--after footfall. Just under half the population tends to overpronate.

Overpronation can cause some problems if not corrected for. During a run, your feet are asked to withstand the repetitive task of shock absorption. A person who overpronates is repeatedly putting excess torque on the medial, or inner part of the leg.

Shin splints located on the medial part of the leg and medial knee pain are common injuries associated with overpronation.

What about lateral knee pain, you ask? Well, that could be associated with a tight iliotibial band and/or underdeveloped vastus medialis (inner quad muscle) causing the knee cap to track improperly.

Here's my disclaimer: It is always prudent to seek the advice of a medical professional--preferably one familiar with running injuries--when you experience a serious problem that persists.

UNDERPRONATION
Underpronation occurs when a foot strike results in less than four degrees of pronation, leading to inadequate shock absorption.

SUPINATION
Supination is the outward movement of the foot after striking. Supination is very rare--only 2-3% of the population actually supinates, or strikes and then moves outwards. Just because you sprain an ankle by rolling it outwards on a trail does not mean you're a supinator.

Supination is commonly confused with UNDERPRONATION, the lack of movement inward.

NEUTRAL
Neutral runners are the lucky ones. They pronate just enough to absorb the shock, and not too much to cause strain on the lower legs and knees.

Okay, now that we know the biomechanical terms, how do you decide where you fit in?

Well, there are some general rules to go by, but like all rules they tend to be broken...

Generally, individuals with a high arch tend to have a rigid foot structure which doesn't give much, i.e. doesn't pronate much. High arches are usually neutral or underpronators.

Conversely, most individuals with flat arches tend to overpronate. However, after working in a specialty running store for several years, I have seen more exceptions than I care to mention here.

The best way to determine your individual foot biomechanics is to undergo a more thorough test. This involves another person such as your coach or running partner. Of course, most specialty running stores are staffed with people who can give you an experienced eye when it comes to determining your individual foot structure.

The first thing I do when examining a foot structure is have the person stand naturally, looking straight ahead, with shoes off and pant cuffs rolled well above the ankles (shorts work the best.)

What does the arch look like? How high? How flat? Next, what does the sub-talar joint look like? (This is the pointy ankle bone on the inside of your leg.) Is is in a neutral position? Or does it collapse inward a bit while standing? The more feet you look at, the better you'll become at recognizing what's what.

A high arch with a neutral sub-talar joint tends toward a neutral to underpronating gait. A sub-talar joint that is less than neutral, which is often accompanied by flatter arches, is a sign of overpronation.

The next test is the walking test--we find out what happens when movement takes place! Walk normally for about ten meters and then back. Your analyzer should focus on what the sub-talar joint is doing after foot strike. Remember, four to six degrees of pronation is needed, but much more than that is heading into overpronation territory.

At this point, you should have a pretty good idea of how to describe your biomechanics--overpronator, neutral, underpronator. This brings us to the next topic--shoe types--and the ultimate test--running in your chosen shoes.

But first, a few words on the foot strike and the dispelling of a common myth.

Most people are heel strikers, and as such, land on the outside (lateral) corner of the heel. It doesn't matter if you're neutral, an overpronator or an underpronator, the outside corner of your shoe is where you land. Thus, this tends to wear the most.

It is a common misconception that if you wear down the outside heel of your shoes, you must be a supinator (although knowing the terms better, you might say underpronator.)

Reading shoe wear is an interesting art, although looking at the feet tells us more. That's why we went through the analysis above. Only in extreme cases, or extremely worn shoes does the wear pattern tell us much. If you're replacing your shoes on a regular basis--every 400 to 800 miles--then the only wear usually seen is on the outside corner of the heel.

Now...

TYPES OF RUNNING SHOES

STABILITY SHOES
You can spot a stability shoe by picking it up and looking at the medial (inner) side. You will often see a darker color (gray) or some sort of plug, often called a roll-bar or footbridge. This darker material is denser than the surrounding (white) material. By the way, this material is usually either EVA (ethyl vinyl acetate) or PU (polyurethane). Both are standard cushioning materials.

The idea is that the denser material will slow down the pronation (movement inward.) Remember, the foot strikes on the outside heel and then pronates to absorb the shock of footfall. Overpronators move inward too much and the denser material is designed to eliminate the excessive motion.

With that said, stability shoes work well for overpronators. Stability shoes are usually built on a semi-curved last to accommodate a bit of an arch.

MOTION CONTROL SHOES
Motion control shoes are more extreme than stability shoes. You'll still find the darker (denoting denser) material and/or plug on the medial side. In addition, the last is straight to accommodate flatter arches. Motion control shoes are for extreme overpronators.

NEUTRAL (CUSHIONED SHOES)
Neutral shoes have a uniform color and uniform density throughout the midsole. Neutral shoes are for neutral runners and udnerpronators. And yes, they are for the 2-3% that supinate, too.

Underpronators and supinators need shoes that encourage pronation. Thus, underpronators and supinators should avoid stability/motion control shoes and look for a neutral shoe with a decent amount of cushioning.

Note that the common name for neutral shoes is CUSHIONED SHOES. Don't let this confuse you. All shoes have a cushioning system. An extreme overpronator may want a shoe with lots of cushioning, but does not want a CUSHIONED SHOE. Rather, a MOTION CONTROL SHOE is needed.

Okay, you should be armed with enough knowledge to know what kind of shoe you're looking for. For those interested in more details, I will now throw in some further bits of information for your studying enjoyment.

CUSHIONING SYSTEMS
Every manufacturer has its own patented cushioning technology. Asics uses Gel, a pliable gel-like substance. Adidas uses Adiprene, similar in structure to the Sorbothane insoles you might find in a shoe store. Brooks uses Hydroflow, a viscous, encapsulated liquid. Nike uses Air, which is...well, air. New Balance uses Absorb, a soft gel-like pad. Saucony uses the Grid, which looks like the soft part of two tennis rackets put together with air in between. You get the idea.

Which is better? It depends upon which rep you ask. Suffice it to say they are all comparable. Some runners tend to like one over another, a matter of personal preference.

In addition to each company's special cushioning technology, EVA (ethyl vinyl acetate) or PU (polyurethane) are also used. These are simply standard cushioning materials.

FIT
If the shoe fits, wear it...assuming it supports your biomechanical needs. Every running shoe company makes the different categories of shoes--stability, motion control, and cushioned (neutral.) And every company uses a different last (the cut-out upon which the shoe is made.) So try on several pairs until you find one with the appropriate width for your foot.

As for length, make sure you have about a half-inch at the end. It makes sense to try on shoes with the same type of sock you run in. And if possible, try on new shoes after you've done a run or later in the day. This accounts for the swelling that invariably occurs in your feet during a run.

Oh, and don't be alarmed if you wear a size and a half bigger in your running shoes than in your street shoes. This is a phenomenon known as "shoe creep." In a competition to weigh less, it seems running shoe sizes have gradually shrunk over the years. Of course, feet do get bigger as we age, too! So, go by how the shoe feels, not by what the number says.

And go buy your shoes!

André Zapatos is the official shoe guru at Rocky Mountain Runner. He has a degree in biology, several years experience coaching runners and track, and has worked in a specialty running shoe store for longer than he cares to admit. Please submit your shoe questions to André and he will answer them in his column here.

The Shoe Guru has gone on sabbatical. For help with your running shoe questions, call the experienced staff at Runners Choice in Boulder: 303-449-7548.