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How to Steer Patients Toward the Right Sport Shoe

D.R. Martin

THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 9 - SEPTEMBER 97


The athletic shoe industry continues to offer new features and technologies, but the basic criteria for choosing athletic shoes remain the same as ever—comfort and safety. New developments such as unique designs for women and new lacing systems have improved shoe fit. Beyond the fit, knowledge of foot types and of the demands of each sport helps physicians guide patients toward shoes that will help them avoid injuries.

The abundant marketing glitz and hoopla may suggest that athletic shoes have undergone a revolution in recent years. They haven't. Rather, the trend has been a steady evolution in design and materials as manufacturers have sought to improve safety and performance.

"Even if [the shoe industry] had something that was earth-shattering, it would be evolved into place, not thrown into place," says Tom Brunick, director of the Athlete's Foot Stores Research and Development Center in Naperville, Illinois, and footwear editor of Walking magazine.

What's New?

Improvements within the last 4 or 5 years cover a broad range of design details, from the shape of the shoe to new lacing systems.

Options for women. Perhaps the most significant recent advance in athletic footwear is the acknowledgment that women's feet are usually anatomically different from men's and that they therefore benefit from specially designed shoes. A woman's foot is typically narrower than a man's and has a narrower heel relative to the forefoot.

"There are more and more women's shoes that aren't based on downsized or graded men's shoes," says Carol Frey, MD, director of the Orthopedic Foot and Ankle Center in Manhattan Beach, California. "More of them are now being developed based on the shape and function of a female foot. Companies are developing entire female divisions, developing [women's] lasts, the form over which a shoe is made." Shoes built from women's lasts reduce the heel slippage that can occur in downsized men's shoes. Companies that have used women's lasts, according to Frey, include Nike, Asics, and Reebok.

More women than men now buy athletic footwear, and their demands have influenced the athletic shoe market. Though general fitness footwear remains important, competitive female athletes want performance shoes, just like their male counterparts. For example, Nike offers a line of basketball shoes designed specifically for women—11 different styles. Adidas has seven different women's soccer shoes. Brunick says, "You wouldn't have had that 4 years ago."

Midsole changes. The cushioning midsole of athletic shoes has been the "Achilles heel" of shoe design; the ethyl vinyl acetate (EVA) or polyurethane foam used in them breaks down relatively quickly. To improve durability, shoe manufacturers have devised midsoles that encapsulate air or gel; some running-shoe midsoles are cushioned entirely with air. Though midsoles with encapsulated air or gel have never been wear tested, Frey says they do improve durability. "A good guess would be 25% to 50%," she says.

Another recent improvement is better support at the midsole; many companies are inserting support devices, according to Runner's World magazine (1). Older split-sole shoe designs tended to flex incorrectly at the midfoot rather than the forefoot, contributing to problems such as plantar fasciitis.

[FIGURE 1] Laces and loops. Round "laceroni" shoelaces—similar to those used in hiking boots—are starting to show up in athletic shoes (figure 1). Though the new laces untie more readily during use (without double-knotting or lace locks), when used with the new loop or web eyelets, they slide more easily through a shoe's loops and distribute the pressure across the top of the foot more evenly than flat laces.

Glenn Pfeffer, MD, an orthopedic surgeon and assistant clinical professor at the University of California, San Francisco, says the new laces allow a better fit than flat laces do. "They don't kink, they don't cause pressure points, and they glide easily," he says.

Neoprene sleeves. New shoe technology usually appears first in running shoes, and the latest development is the neoprene sleeve—an elasticized, padded cuff around the opening of the shoe. Neoprene sleeves "keep the shoe from pistoning up and down as you run," says Frey. "It gives you a better fit and grips the foot."

Thinner midsoles. In court shoes, the trend is to bring athletes closer to the court by reducing the thickness of the midsole, yet still provide good cushioning. Thinner midsoles lower the athlete's center of gravity and reduce side-to-side ankle motion.

Good Fit, Bad Fit

If female-specific shoes, "laceroni," and neoprene sleeves were merely marketing gambits, they would merit little notice. However, they are providing active people and athletes with improvements that augment the fit and therefore the safety of athletic footwear. Poorly fitted shoes, after all, can cause many difficulties that don't happen when shoes fit well.

"Even the smallest [fit] problem can prevent athletes from performing to the best of their capabilities," writes Tom Clanton, MD, chair of the department of orthopedic surgery at the University of Texas Medical School at Houston (2). Medical conditions that can arise from improper shoe fit, according to Clanton, include new-onset bunion pain (from narrow shoes or those with rigid material covering the forefoot), metatarsalgia or Morton's neuroma (shoes that are too tight across the forefoot), and black toe (a shallow toe box). Toe deformities such as hammer toe, claw toe, and overlapping fifth toe may become symptomatic in athletes whose shoes have toe boxes that are either too narrow or too shallow. Though calluses and blisters are more or less expected in many sports, they are more common with a shoe that rubs the skin excessively or allows the foot to move or slide around.

Physicians and other health professionals can help point patients who ask about shoes in the right direction. (See "Special Issues Guide Hiking Boot Choice," below, and "Athletic Shoes: Finding a Good Match") The physician can start by showing the patient the type of arch he or she has: high (pes cavus), medium, or low (pes valgus).

About 25% of the population needs some type of specialized shoe, says Pfeffer: patients who
are flat-footed, are pronators, or have very high arches. "What should come to the doctor's mind are the two Cs—cushioning or control," says Pfeffer. "Patients who have very high-arched feet have very stiff feet, and they need cushioning. Patients who have flat feet and are prone to a lot of motion need a shoe that can control that motion," he says.

The average foot needs a middle style of shoe—one that's not too hard or too soft, says Michael Lowe, DPM, a podiatrist in Salt Lake City and president of the American Academy of Podiatric Sports Medicine. "That midrange is going to give you a nice, stable, functional kind of shoe," he says.

A patient's arch determines which type of last, or shape, the shoe should have (figure 2). Patients who have low arches do best in a shoe that has a straight shape and a board last; those who have high arches require a shoe with a curved shape and slip-lasted construction; and those who have a medium arch benefit from one that has a semicurved shape with a combination last.

[FIGURE 2]

Obviously, active people are wise to try a shoe on before buying it. That usually means buying at a retail store rather than by mail order or on the Internet. Physicians can help pick a good store. Clanton, for example, recommends that physicians develop a relationship with a local shoe store. "I've gone to several different shoe stores and tried on shoes myself and talked with some of the salesmen," he says. "I've gotten an idea of stores where I feel like my patients could benefit from the knowledge of the people there. That's where I make referrals."

Also, to help patients select correctly sized shoes, Clanton provides them with shoe-fit cards. He traces the patient's foot on a piece of paper, cuts an index card to match the tracing of the widest part of the foot, and then cuts out a half-inch notch where the card is the widest. The patient can place the card against the ball area of shoes being considered. Shoes narrower than the card may cause problems; shoes narrower than the notched width are almost certain to.

Patients should be reminded to consider their past foot problems when selecting new athletic shoes, says Pierce Scranton, MD, an associate clinical professor at the University of Washington. For example, if the patient has a history of repeated ankle sprains, perhaps he or she should select high-topped rather than low-topped aerobic shoes or cross-trainers.

A Role in Injury Prevention

Besides comfort, injury prevention is what athletic shoes are all about. Shoes for running and other foot-strike activities are designed to prevent stress fractures, and shoes for court sports are designed to prevent ankle sprains.

"If you look at overall injuries and problems created by shoes, fit is the number one consideration," says Clanton. However, he says researchers focus not on how well shoes fit, but on how cushioning and control features prevent injuries. One study (3) put Israeli military recruits into modified basketball shoes, substantially reducing the incidence of metatarsal stress fractures that related to regular military boots. Other research has produced similar findings (4). It's also been suggested that inadequate cushioning in shoes can cause injuries to runners (5).

Shoe traction plays a role in preventing knee injuries such as noncontact anterior cruciate ligament ruptures. Traction is a particular issue with court and cleated sports shoes in regards to their interface with the playing surface. Frey explains that proper traction depends on the specific sport; too little traction may impair athletic performance, while too much traction increases the risk of injury.

Clanton says that while collegiate and professional athletes are apt to take the risk of higher-traction footwear for performance's sake, it makes little sense for people at the high school or less competitive levels to chance serious knee injuries.

Shorter cleats on football shoes or use of soccer shoes, for example, have been shown to reduce knee and ankle injuries in high-school football players (6,7). Clanton recommends that cleats on a shoe for younger people be no longer than one-half inch.

Scranton, team physician for the Seattle Seahawks of the National Football League, recalls a football shoe that was designed for play on snow and ice that could generate incredible torque. "My concern is that some starstruck kid, on a hot summer day, remembers seeing the Green Bay Packers slug it out on an ice-covered field wearing [this shoe]," he says, "and he goes down to the store and orders them."

Traction concerns can also apply to court shoes, since the friction produced by the outer sole depends on the material used and its interaction with the playing surface. "Different surfaces have different characteristics related to the shoes, and while the human body can adapt to a great degree, there are different exposure rates to injury based on traction," Scranton says.

Clanton says understanding of the shoe-surface interface hasn't advanced enough to warrant specific recommendations to athletes. "But it has become clear that friction is a critical factor in injury rates," he says. One study (8) has suggested that shoe manufacturers provide indications and suggested playing surface conditions for their shoes.

Scranton says that what's needed is "the development of a shoe that has good frictional characteristics but that will not 'Velcro' to a surface—whether it be a cleated shoe getting stuck in natural grass or a turf shoe getting stuck on a dry, hot field on a summer day."

Pairing Shoes With Sports

In general, patients who participate in a certain sport or type of exercise three or more times a week should wear shoes designed for that activity. This will avoid problems such as the higher midsoles that cushion running shoes creating instability during the lateral movements of aerobics and court sports like tennis or basketball, and court shoes lacking the cushioning that running requires.

Cross-training shoes combine some elements of both running and court shoes, says Lowe. "For low mileage in either activity they're moderately successful, and they function well as a walking shoe," he says "We're very comfortable placing our couch-potato patients in a cross-training shoe and letting them do multiple activities."

Patients whose main activity is walking should be advised to consider a shoe designed for walking, says Pfeffer. "It has a much more cushioned heel and a stiffer midsole [than joggers], and more spring in the toe to encourage the follow-through when toeing off."

Health and Comfort

The human foot is a remarkable structure that comes in many shapes and sizes. It's asked to bear extraordinary loads and strain. A 200-lb man, for example, lands with up to 600 lb of force on each foot several thousand times in a few miles of running. But with appropriate footwear, athletes and duffers alike can help keep pain and injuries at bay and enjoy the physical activities they choose.

"I would bet that if we were allowed to wear athletic shoes to work we could save the healthcare system in excess of a billion dollars a year," says Pfeffer. "These shoes are comfortable, and what's comfortable is probably what's healthy."

References

  1. Wischina B, Brunick T: Spring 1997 shoe buyer's guide. Runner's World 1997;32(4):50
  2. Clanton TO: Sport shoes, insoles, and orthoses, in DeLee J, Drez D, Stanitski CL (eds), Orthopaedic Sports Medicine: Principles and Practice. Philadelphia, WB Saunders, 1994, pp 1982-2021
  3. Milgrom C, Giladi M, Kashtan H, et al: A prospective study of the effect of a shock-absorbing orthotic device on the incidence of stress fractures in military recruits. Foot Ankle 1985;6(2):101-104
  4. Frey C: Footwear and stress structures. Clin Sports Med 1997;16(2):249-256
  5. Gardner LI Jr, Dziados JE, Jones BH, et al; Prevention of lower extremity stress fracture: a controlled trial of a shock absorbent insole. Am J Public Health 1988;78(12):1563-1567
  6. Torg JS, Quedenfeld T: Knee and ankle injuries traced to shoes and cleats. Phys Sportsmed 1973;1(2):39-43
  7. Torg JS, Quedenfeld TC, Landau S: Football shoes and playing surfaces: from safe to unsafe. Phys Sportsmed 1973;1(3):51-54
  8. Heidt RS Jr, Dormer SG, Cawley PW, et al: Differences in friction and torsional resistance in athletic shoe-turf surface interfaces. Am J Sports Med 1996;24(6):834-842


Special Issues Guide Hiking Boot Choice

Hiking boots are perhaps the most costly off-the-shelf sport footwear, with $250 price tags not uncommon for high-end models. But for serious hikers and backpackers, there's no more vital piece of gear. The wrong boot can lead to a sprained ankle or broken leg miles from help. It can even mean the difference between life and death.

Hiking boot selection is guided by the wearer's hiking level, says Steven Zell, MD, associate professor of medicine at the University of Nevada School of Medicine in Reno and an experienced back-country hiker. He cowrote the chapter on medical equipment and supplies in Wilderness Medicine: Management of Wilderness and Environmental Emergencies (1).

Zell says an ideal hiking boot for serious hikers should support an adult and a pack of up to 100 lb with a high center of gravity. The upper should be full-grain leather reaching above the ankle, and the boot should have a shank running through a thick sole for torsional rigidity. For good breathability, patients should seek a good-quality boot made from leather at critical support areas and a breathable waterproof material such as Gore-Tex.

A casual hiker probably won't be carrying much more than a small day pack or fanny pack. His or her center of gravity is lower, so there's less torsion on the ankle. In case of a misstep, the day hiker can more easily maintain an upright posture. Such a hiker, says Zell, can wear a day boot that's light and breathable. Michael Lowe, DPM, a podiatrist in Salt Lake City and president of the American Academy of Podiatric Sports Medicine, suggests at least a three-quarter top for day boots.

Patients should be aware that some shoes on the market look like hiking boots, but lack a steel, carbon resin, or fiberboard shank that provides the necessary support and torsional stability. Lowe teaches patients to grab the heel and forefoot and bend the boot or shoe upward. "The boot they buy should bend across the toes, not across the midfoot," he says.

Socks are also an important part of the hiking boot equation, says Lowe. Acrylic socks are preferred because they don't compress and they wick moisture away from the foot. "They're warmer in the winter, cooler in the summer, and virtually don't wear out," he says. "We significantly decrease blister formation with them."

In no other athletic shoe is break-in more important than in hiking boots, since they're so much stiffer. Break-in allows hikers to know what to expect on the trail, says Tom Clanton, MD, chair of the department of orthopedic surgery at the University of Texas Medical School at Houston. To break in the boots, patients should wear them at home for a couple weeks and during a few short day hikes. Clayton says, "The fit and relationship of the boot to the foot is probably more critical than in just about any other situation."

Reference

  1. Zell S, Goodman P: Wilderness equipment and medical supplies, in Auerbach PS: Wilderness Medicine: Management of Wilderness and Environmental Emergencies, ed 3. St Louis, CV Mosby, 1995, pp 413-445


D.R. Martin is a medical journalist and copywriter in Minneapolis.


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