As all runners know, running begins with a good foundation. And where do we find that foundation? At the ground level, where the rubber meets the road.
In other words, your shoes — the pieces of leather and rubber that separate your feet from the hard concrete of the road.
Let’s look at the anatomy of a running shoe and the four sections that make it complete.
The Uppers
The uppers of the shoe may be made of leather or, for lighter shoes, a synthetic that is lighter, washable, and breathable (to reduce heat from the foot).
Another component of the upper is the shoe’s tongue, which should be padded to cushion the top of the foot against lace pressure. At the back of the shoe, the ankle collar should also be padded to prevent rubbing and irritation of the Achilles tendon.
The Outersole
The outer sole is the treaded layer glued to the bottom of the midsole. It resists wear, provides traction, and absorbs shock. This is probably the most important layer for the “street fighter” or road runner.
The outer sole usually consists of blown rubber, hard carbon rubber, or a combination of both. Blown rubber is the lightest, but it is not as durable as pure carbon.
Stud or waffle outer soles are excellent for running on soft surfaces such as grass or dirt, as they improve traction and stability. On the flip side, the ripple sole is better designed for running on asphalt or concrete.
The Heel Counter
The heel counter is the inflexible material surrounding the heel. It must be both rigid and durable to support and stabilize the heel.
Just look at any old shoes, and you will see the wear and breakdown of the inner heel counter, which tends to lose its stiffness over time. That’s why an external counter is typically placed between the midsole and the base of the heel counter.
You will also see a wedge that adds heel height and enhances the shoe’s ability to absorb shock and reduce strain. The added heel height shortens the Achilles tendon and the gastrocnemius-soleus muscles, reducing strain on these important posterior running structures.
The downside is that a higher heel height may feel less stable, causing reduced flexibility in the tendon structure.
The Midsole
The midsole is located between the outer sole and the upper. Many regard it as the most important part of the running shoe. It provides cushioning and shock absorption while also controlling excessive foot motion (pronation/supination).
Midsole Materials
The primary materials used in midsoles are ethylene vinyl acetate (EVA) and polyurethane (PU).
EVA is a lightweight foam with good to excellent cushioning. The problem is that this material breaks down quickly — it can even break down just sitting in a box in your closet. Compression-molded EVA is one answer, making it harder and more durable.
PU is also a foam, usually denser, heavier, and more durable than EVA. PU will stand up longer, but you will give up some of that precious cushioning in return.
Cushioning Technology
Most shoes today are cushioned with gel, foam, or other manufacturer-specific materials designed within the midsole. This type of cushioning extends the life of the midsole while adding increased stability and shock absorption.
This is typically where you will see the greatest quality difference between various companies’ shoes and models — and this is where the technology wars are being waged.
Shock Absorption vs. Motion Control
Remember, shock absorption depends on how compressible the midsole material is. The more the material compresses, the more movement there is within the shoe.
The less the material compresses, the better the shoe’s motion control — but there is a tradeoff in shock absorption. In this case, the shoe may feel harder and not as soft.
Know Your Foot Type
So, how important is it to know what type of foot you have and how you run?
Very important! You need to know the basics of running gait and foot types.
The Running Gait Cycle
When you run, the heel strikes the ground first, usually on the outside (supination). Next, the foot rolls inward and flattens out along the longitudinal arch (pronation).
The foot then resupinates by rolling through the ball and rotating outward. At this point, the foot becomes a rigid lever as it prepares to push off the ground.
To find a runner who supinates or pronates just the right amount is rare. Typically, most runners — particularly those who become injured with knee pain, Achilles tendonitis, shin splints, IT band issues, or heel pain — suffer from either excessive pronation or supination.
Overpronation
Everyone thinks pronation is evil. Wrong! Your foot needs to pronate to adapt to uneven surfaces. We all have to pronate to a certain degree.
However, excessive pronators — whose feet roll inward too much while running — are the runners most likely to develop overuse injuries. The overpronator generally has a flat foot (low arches).
You can check this yourself by wetting your feet and walking on a piece of paper. If you see the whole footprint, including the arch, you can bet you’re an overpronator. If you check an old pair of shoes, you’ll see a wear pattern on the inside, particularly around the big toe.
Overpronators generally have flexible feet, which creates a very unstable foot. This can lead to many of the overuse injuries previously mentioned. If you are an overpronator, look for a shoe with ample motion control, preferably with a board last. A straight-lasted shoe is also recommended for overpronators.
Supination
What about supinators? The supinator’s feet typically roll outward, both in the heel and in the forefoot. These are the runners with high arches.
To check your foot type, wet your feet and walk on a piece of paper. If you only see a wet spot on your heel and the ball of your foot, you know you oversupinate. When you look at an old pair of shoes, you’ll see excessive wear on the outside border of the heel and on the outside of the forefoot near your little toe.
Supinators are definitely in the minority compared to pronators.
The high-arched supinator’s feet are more rigid and cannot absorb shock as well as an overpronator’s feet. With a rigid foot, the supinator is subject to more lateral ankle sprains, stress fractures, and pain on the outside of the shin and knee.
Supinators should look for a shoe with better-than-normal cushioning for added shock absorption, as well as flexibility. Many supinators feel more comfortable with a semi-curved or curved last because of the shape of their feet.
Shopping Tips
So what are some tips for selecting a good running shoe? Both the American Running and Fitness Association and the American Academy of Podiatric Sports Medicine make the following recommendations:
- Try on both shoes, because your feet may not be the same size, and the shoes may not be made symmetrically. Walk and jog around the store for a few minutes; climb stairs, or try jogging on a treadmill if available.
- Try on a couple of different models and sizes to make a good comparison. Don’t rush your selection.
- The lacing area and tongue should be padded, especially if you have a bony bump (met-cuneiform) on your instep.
- Be sure the sole flexes easily where your foot flexes. Buy shoes with removable insoles so you can modify or replace them with orthotics as needed.
- Allow a half-inch in front of your longest toe when you stand up. Fit shoes in the afternoon or after a workout, when your feet are at their largest. Feet swell as much as a full size during a good workout.
- The key to finding the best shoe is comfort, not price or brand name. Don’t rely on a break-in period; shoes should feel good the day you buy them.
- The toe box should allow your toes room to move around. The mid-part of the shoe, when laced, should hold your foot snugly so that it doesn’t slide forward and jam your toes with each step. If the shoe feels tight across your instep, start the laces on the second pair of eyelets.
- The heel counter should fit snugly so your heel won’t slip and rub.
- Check the quality control of the shoes. Put them on a flat surface near eye level. The mid-line of the heel counter should be perpendicular to the surface.
- Try on shoes with the socks, inserts, or orthotic devices you plan on wearing.
Invest in the Right Shoes Today
When looking for a good running shoe, start by selecting a quality specialty running shoe store with competent salespeople. They know the latest in shoe design and performance.
Typically, these “fitters” are runners just like you. They’ve been hired because of their love of running and their interest in their fellow runners. Search them out and develop a relationship with a store and a person who has been fitting shoes for some time.
If you have a history of injury from a shoe or a biomechanical problem, contact Dr. Sweeney. He will be able to detect the source of the problem and recommend the right shoe for you.