IF THE SHOE FITS…

The way people run varies considerably and a shoe that’s right for one person can cause another blisters, musculoskeletal strains or joint inflammation. Twenty years ago, the only criteria for buying sneakers was ensuring that the toes didn’t jam against the end of the toe box. Today however, shoe design has become quite sophisticated with a wide variety of choices available. It has become necessary for physical therapists to assess foot biomechanics and running style in order to provide the patient with helpful information in choosing the correct shoe.

CHECKING THE PATIENT’S FEET

  It is important to determine if a patient is a pronator or a supinator. This can be done by drawing a line bisecting the Achilles tendon and the calcaneus. The alignment of these marks is evaluated with the patient in standing. If the calcaneal line tilts medially then the foot has a tendency to pronate. Conversely, if the calcaneal line tilts laterally then the foot has a tendency to supinate[20].

Another clinical technique use to determine foot posture is to palpate the talar dome. This is done with the patient standing. If the talus is more palpable medially then the foot is in a pronated position,  if the lateral aspect of the talus is more palpable the foot is in a supinated position.

CHECKING THE WEAR PATTERN OF THE PATIENT’S SHOES

A running shoe, when placed on a flat level surface should not be biased medially or laterally. The main purpose of the shoe is to hold the foot stable. It should be constructed so its upper, midsole and outsole is firmly attached (Figure 1). The uppers, heel counter and the sole should be straight. The shoes should not rock from side to side and the shock absorbing pockets should resist collapsing under load. Defective or worn out shoes which don’t hold feet in a neutral position may accentuate a preexisting musculoskeletal imbalance (i.e. excessive pronation or supination). This may lead to unnecessary aches and pains and, if not treated, a more serious or permanent injury.

The importance of carefully inspecting running shoes for manufacturer’s defects  before purchase, and regular checks for uneven or excessive wear throughout the life of the shoe can not be overemphasized. The following guidelines will help the athlete avoid buying defective running shoes and may prevent unnecessary injuries.

The shoe should be glued together securely. Test this by holding the shoe and trying to pull the upper part of the shoe away from the midsole, and the midsole from the outsole (Figure 2). Any separation will weaken the shoe’s support.

The upper part of the shoe should be glued straight into the sole. Test this by putting the shoe on a level surface and inspect the back of the shoe (Figure 3A). The heel counter should appear even and should not lean to the right (Figure 3B) or left. A brand new shoe that leans medially or laterally could cause injury especially if there is a large asymmetry between each shoe of a pair.

The sole of the shoe should be level to the surface on which the shoe is resting. Test this by checking that the medial and lateral aspect of the heel is even when resting on  a flat, level surface (Figure 4A and B). Compare each shoe individually, then compare the right to the left shoe for symmetry. An asymmetry of two millimeters can tilt the shoe in or out significantly.

Test for asymmetry by applying a downward medial and a downward lateral force to both the right and the left shoe to see if the shoe rocks medially and/or laterally (Figure 5A and B).  Check for this asymmetry from side to side within each shoe. The shoes should remain even and not roll. If they roll when they are new, they will not stop the foot from rolling excessively when worn, and can cause injury.

Air pockets and gel pockets must be inflated evenly. Test this by pushing on the sides of the air pockets medial to lateral, and lateral to medial to check for symmetry of inflation (Figure 6). Push down into the air pockets both medially and laterally from the top of the pocket (Figure 7A and B). If the pockets are inflated unevenly, this may cause the shoe to collapse unevenly, and the foot to roll when it hits the ground.

THE LIFE OF THE SHOE…

A good running shoe lasts, on average, about 300 – 500 miles. The mileage could be less if the shoes get wet in a hot, humid environment or from running in the rain. The average runner who runs 30 miles per week with normal wear and tear can expect to have a shoe life of about 10 – 15 weeks. It is a good idea to put a date somewhere on the shoes to track how long they’ve been in use. Shoes should also be checked periodically for signs of premature wear since shoes that are no longer in alignment cannot keep the foot and leg in a neutral position.

With long distance runners, mileage increases dramatically while they are training for a competitive event. However, it is not unusual for shoe models to be discontinued and a favorite shoe may suddenly become unavailable. So, it makes sense to buy an extra pair before a long training program, and put 40 to 50 dry miles on them. This will break the shoes in and this pair can then be put away in the closet until the big race.

PRICE DOES NOT ALWAYS DETERMINE QUALITY…

The principal author, in conjunction with a feature story for a local television station, examined a variety of shoes (all different brands and styles) from several different sporting goods stores. The result was an alarming 30 – 50% defective rate. Surprisingly, more expensive shoes did not necessarily mean better built shoes. Even the most expensive designer brand running shoes were not exempt from a number of manufacturer’s defects.

SUMMARY…

The type of running shoe worn by an athlete can be a very important factor in the prevention and treatment of lower extremity overuse running injuries. Our experience indicates the importance of checking the construction of the patient’s running shoes as a possible cause of injury, particularly when other more common factors are eliminated by clinical evaluation and assessment.

Additionally, when defective or excessively worn shoes are found to be the cause of any injury, it is vital that the clinician educate the patient as to the nature of the problem. Knowing the difference between poor and good athletic shoe construction and carefully checking running shoes for manufacturer’s defects prior to purchase will prevent unnecessary injury to the patient who runs frequently for exercise or competition.

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AMAA member, Bruce Wilk, is a board certified orthopedic physical therapist and director of Orthopedic Rehabilitation Specialists. William Gutierrez is a board certified orthopedic physical therapist and certified athletic trainer at Orthopedic Rehabilitation Specialists. Orthopedic Rehabilitation Specialists is located at 8720 North Kendall Drive, Suite 206 Miami Florida 33176, and can be reached by calling (305) 595-9425 or at ORS@icanect.net .

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