Sports Shoes: The Danger Underfoot

Just like finding the proper formula for nutrition and exercise, it’s up to you to find the right shoes for your feet. That may sound simple, but the truth is most shoes — even the ones in the impressive television ads — can be hazardous to your health. Most modern exercise shoes offer too much support, are too heavy, and have too-thick soles. What’s more, many people are wearing the wrong size. The result is a formula for injury.

Biomechanically incorrect shoes can cause physical stress throughout your body, and contribute to injuries from the foot, ankle and knee to the hips, spine and other areas. Scientific studies show that the so-called protective features found in many shoes, including shock absorption and motion control, actually increase the likelihood of injury. For instance, some support systems can weaken your ankles, and soft, cushioned shoes can potentially lead to instability of the knee joint and other areas. Furthermore, the thicker the sole, the more unstable your foot and ankle become.

Many of these oversupported shoes are also overweight. The seemingly insignificant weight added to your feet, in the course of the day or workout, produces large negative effects in the economy of locomotion. For example, for every 3 ounces of shoe weight, a 1 percent increase in oxygen uptake is required for the same performance.

The soles of your feet have millions of nerve endings that sense the gravitational stress of standing and each step you take. This information is sent to the brain, which works together with your body to adapt to this stress by constantly adjusting your body during movement. This normal protective mechanism is meant to keep you from accumulating excess wear and tear, and from being injured. When you cover the foot with a shoe, you risk interfering with this adaptive mechanism by preventing the nerve endings on the bottoms of your
feet from sensing and sending vital information to the brain. The more the foot is covered with thick, insulating materials, the more interference with the body’s natural mechanisms. The result is a diminished ability by the foot and the rest of the body to adapt to normal activity, with potential damage to the ligaments, fascia, cartilage or bones in the foot. Because your feet are your foundation, any instability there could have dire consequences in the legs, knees, pelvis, low back or other areas.

The issue of impact is important, and shoe companies often infer their products protect you against this problem. But impact is normal; it occurs in the foot during walking or training whether a shoe is worn or not. Without a shoe, the body can adapt naturally to impact. With a shoe, there may be interference in that adaptation process.

Barefoot is best because there is no interference with the nerves that sense contact with the ground. Overall, those who are often, or always, barefoot have much fewer foot problems. For example, athletes who run barefoot are injured much less often than those who wear shoes. Unfortunately, this is not practical for most people, though you can still be barefoot whenever possible, such as in your home or backyard. And if you live near a beach or a grassy area you can also do some barefoot walking or running on these surfaces.

What to Wear?

The reality is that most people will have to wear shoes when going outside. When buying shoes, there are some things to consider. Look for shoes that are relatively flat and natural, ones that don’t oversupport your foot or raise it off the ground too much. Many companies make these shoes, but in lesser numbers than the oversupported ones. In addition, a few running shoes called “racing flats” are built with less sole to come between your foot and the ground. Above all, forget the hype you hear about shoes. Consider the fact that one study of 5,000 runners showed that those using more-expensive running shoes with more shock-absorbing materials had a higher incidence of injury. It seems there is less chance of developing problems in less-expensive shoes. The main reason for wearing them is not support, but rather to protect the bottoms of your feet.

Excess heel height can also increase pronation, especially in shoes with heels that are thicker than about 1 inch. Too much heel height can also causes the entire body to move abnormally.

A significant problem with thicker heels and soles is foot strike. The natural running gait results in mid- to forefoot strike, depending on how fast the pace. But the thick soles used in today’s running shoes, for example, forces you to land on your heels — this is not natural and a significant mechanical stress. Try running barefoot, and no matter how slow or fast you go it will be almost impossible to land on your heel. (Landing on the heel is a normal walking gait.)

In general, shoes with more cushioning are also likely to produce excessive pronation, a falling inward of the foot’s inner, medial arch. This is especially true of shoes with added soft midsole material. Many shoe-support systems, including orthotics, can interfere with the normal functioning of the medial arch, the most important of three main arches in the foot. I have only on rare occasions recommended orthotics, and only for a short time while the cause of the problem was being corrected.

Sorbothane and similar materials commonly used in exercise shoes and after-market insoles can also be counter-productive. While tests on machines demonstrate Sorbothane’s great energy-absorbing abilities, a study on humans shows that insoles made of this material actually increase leg stress by 26 percent, enough to cause stress fractures. Beware: The muscles of your foot and leg, especially the calf muscles, have adapted to the thickness of your shoe. If you suddenly change your shoe style by wearing flatter shoes, your muscles may have to re-adjust their length. This may take a couple of weeks, during which you may experience some calf discomfort

Sizing Up Your Shoes

A significant number of people are wearing everyday, dress or exercise shoes that are too small. In addition to foot problems, this can cause pain or dysfunction in the ankle, leg, knee, hip, low back, and at times as high up as the neck or TMJ (jaw) joint. And most often, the feet don’t even hurt. Astudy done in my clinic over an 18-month period found 52 percent of all athletes were training in shoes that were too small. Once the problem was diagnosed, these patients usually required a change from one-half to one-and-one-half sizes larger.
Another study by orthopedic surgeons showed that 88 percent of women wore everyday shoes that were too small.

Case History

Jim had seen eight different professionals for his problems. Because his symptoms were in both knees, most of their therapeutic attention was directed there. But it was Jim’s workout shoes that told the real story. His right shoe had an area where the large toenail had worn through. Upon measuring his foot, it was found that his shoes were one entire size too small. “I thought they should be snug,” he said. After wearing the correct-size shoes for a week, Jim was able to exercise painlessly for the first time in two-and-a-half years.

You might think that the size of your feet is set by age 20, but that’s not true. Normal increases in size, as a result of changes in weight, muscular imbalance or pregnancy, often occur regardless of age. Just being on your feet a lot can increase their size. This is due to the stretching or elongation of the ligaments and tendons, followed by a spreading of the bones in the foot. If you don’t keep up with these changes by wearing larger-size shoes, you can create a major physical stress.

Wearing a shoe that’s too small can cause a slow inward jamming of the toes, characteristically causing a backward subluxation of the first metatarsal joint, though any toe can be involved. This creates a mechanical instability in the foot which, if left uncorrected, can lead to other foot and ankle problems such as hammertoes and bunions. In time, the toes become spring-like; when a small shoe is slipped on, the toes spring in, and the tightness of the shoe is not obvious. The first metatarsal joint, however, is not as flexible as the joints of other toes, and therefore takes most of the abuse.

Due to the slow onset of this common problem, the first metatarsal jam is often asymptomatic; if you have it you usually don’t complain of pain in that first toe joint. But visual examination of your feet will often reveal trauma, or micro-trauma (long-lasting mild stress) to the tips of the toes. This often includes discoloration of the nail bed (a darkened toenail), blistering or callousing of the toes, or swelling of the first metatarsal joint (the “ball” of the foot). In more extreme cases, inspection of your shoe will reveal wear and tear, inside and out, as a result of the nail or front of the toe trying to push out of the shoe, sometimes causing a hole in the shoe.

Looking inside the shoe helps diagnose the problem. If you have a removable insole, take it out and study it. Look at the wear pattern (especially the indentation made from the toes), and see if the areas compressed by the toes are not completely on the insert, as they should be. Toes that overlap the top of the insert obviously indicate a too-small shoe.

The importance of proper-fitting shoes can’t be overemphasized. Here are some tips on finding an ideal-fitting shoe.Always measure your foot when buying shoes. After a certain age, many people don’t have their feet measured when buying new shoes, since they don’t realize their size could have changed. As a result, the same shoe size is worn for years, or even decades.

Have both feet measured by a competent shoe-store salesperson, in a standing position on a hard floor. Do this at the end of the day, since most people’s feet are slightly larger then, compared to the morning. (Of course, any meaningful daily size fluctuations must be differentiated from serious health problems, such as edema and certain pathological changes.) Use these sizes only as a gauge — the devices used for this measurement are consistent, but the sizes marked in the shoes aren’t. Asize 9 from one company may be more like an 8 from another. Don’t buy shoes by their size but how they fit each foot. Even the same company may be very inconsistent when it comes to its own size standard.

Spend adequate time trying on shoes in the store. Find a hard surface rather than the thick soft carpet in shoe stores, where almost any shoe will feel good. If there’s no sturdy floor to walk on, ask if you can walk outside. If this is not allowed, shop elsewhere.

Try on the size you think you normally wear. Even if that feels fine, try on a half-size larger. If that one feels the same, or even better, try on another half-size larger. Continue trying on larger half-sizes until you find the shoes that are obviously too large. Then go back to the previous half-size; usually that’s the one that fits best. You may need to try different widths when available to get a perfect fit.
Don’t let anyone say you have to break them in before they feel good — the best shoes for you are the ones that feel good right away. Even though you may develop the reputation of being a nuisance at your shoe store, your body will benefit. While many salespeople are aware of how to find the right shoe size, many are not.

For those who have a significant difference of more than a halfsize between their two feet, fit the larger foot.

Many women fit and function better in men’s sports shoes than in women’s. The first rule, though, is that the shoe must fit properly. Some women don’t fit into men’s shoes, and some stores don’t carry men’s shoes in sizes that are small enough.

You may not find the right shoe in the first store you visit. Most outlets carry only a few of the many shoes in the marketplace. Often, shoes from mail-order outlets cost less. But be prepared to ship them back if they don’t fit just right.

Remember, manufacturers design new shoes based on trends of style, color and fancy gimmicks to market the shoe. That’s why shoe styles come and go. If you find the shoe that fits perfectly, buy several pairs. Just be sure to try them all on, since the same shoe style may vary in size

Some patients I worked with bought larger shoes after their initial problem was diagnosed, only to find that their feet kept getting larger. At some point in time, they ended up with an increase of a full size or more. I have occasionally seen increases of two-and-a-half sizes over a two-year period in adults!

This situation is especially a concern for kids, whose feet always seem to be growing. When in doubt, get new shoes. Too expensive? Don’t be afraid to buy some of the inexpensive shoes on the market. The $15 models wear just as long as the fancy ones for $150. Unfortunately, once kids see enough shoe commercials on TV, they may only want the expensive brands

Actually, children should go barefoot as much as possible. When shoes are necessary for children, find them the best-fitting, thinnest shoes with the least support. And that goes for grown-ups too — don’t be afraid to spend as much time as possible barefoot. It not only helps to correct existing problems, but also prevents common foot problems seen in many older people

This information on the potential dangers of shoes is not new. The first published research to show these problems dates back to 1954; electromyographic studies demonstrated poor muscle function in the foot when shoes are worn. Modern shoes are even worse, as many newer studies continue to show.

“High-Tops” Popular basketball shoes — “high-tops” — are promoted as a way to protect the ankles against injury. However, since hightops were made ankle injuries have become the most common injury in the sport of basketball, where almost all athletes use this type of shoe. High-tops are also worn by many people who don’t play basketball. And, like most commonly used “over-thecounter” supports, whether for the ankle, knee or other joints, they often weaken the muscles around the joint, ultimately contributing or even causing a chronic problem. One study showed that during a two-year period, 78 percent of basketball players experienced some type of ankle injury. Of these, 83 percent were recurrent. Studies have not demonstrated that high-top shoes are able to prevent ankle sprains. In fact, Brizuela and colleagues (1997) showed that high-top shoes produced more ankle injuries. These same shoes also reduced the average jump height, and they increased the time needed to complete a short running course in comparison to those who wore low-support shoes — something to consider if you’re playing basketball

 

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