Finding Your Running Shoe
Matching foot type to shoe type

Whether you jog for recreation and fitness or run competitively at a scholastic or masters' level, chances are you have suffered from some type of repetitive stress injury, such as plantar fasciitis, shin splints, or even stress fractures. Although many factors can contribute to a stress injury, you seldom need to look further than your own shoes to find the culprit. It is estimated that impact forces transmitted through the lower leg during running are nearly 21/2 to 3 times body weight. Nearly twice that of walking, the stress on the supporting soft tissues is 4 times greater than that imposed during walking.1 Footwear, however, has been shown to reduce those forces2, becoming an ally in the prevention of injuries among runners. As advantageous as a properly selected shoe is, an improperly selected shoe can increase the magnitude of undesirable forces, and thus predispose you to injury.

Shoes are often selected based on marketing techniques and an appealing design instead of their functional qualities. So how do you know which shoe is best for you? Before choosing a running shoe, you need to know your foot type and the classification of shoe best suited for your foot. Once you know these two factors, you can match them and make a wise decision in purchasing a shoe.

Identifying your foot type
The foot's structure is relatively unique to each individual, and can differ within the same individual from one side to the other. Scientific evaluation of the type of foot one has can be a complicated process, requiring high-tech equipment and slow-motion video; however, most of us can make a general assessment with relative accuracy. Assessment of one's foot type consists of determining the height of the foot's arch, or instep, and then placing the foot in 1 of 3 structural categories. A foot that appears to have an excessively high arch is classified as a pes cavus foot, while a flattened arch is classified as pes planus, more commonly referred to as a flatfoot (Fig. 1).

You can use static or dynamic conditions to determine your foot type. During a static assessment, your foot is held stationary, and you can either stand (weight bearing) or sit (nonweight bearing). For example, during a nonweight-bearing evaluation, visually assess the arch height while sitting on a table without letting your foot touch the ground. A weight-bearing assessment is performed while standing with an equal amount of weight on each foot. A dynamic assessment looks at the way the arch height is maintained while the foot is moving, such as during walking or running. An evaluation of this kind replicates the actual movements and forces the foot undergoes during activity; therefore, it is considered to be more accurate than the static assessment. An accurate self-evaluation can be done by placing your foot in either chalk dust or water and then standing on a small chalkboard or on lightly colored construction paper respectively. Lift one foot off the ground, and while lightly touching a sturdy object for balance, perform a mini squat by slightly bending at the knee of the weight-bearing leg. Return to a normal stance with both feet on the ground. Then, carefully lift your test foot off the board or paper. Based on the appearance of the outline your foot made, you can classify your foot type (Fig. 2). Under dynamic conditions, the individual who maintains a high arch is classified as a supinator, while the individual whose arch flattens excessively is classified as a pronator. Gross assessment of dynamic foot mechanics with the naked eye can be very difficult for even the well-trained clinician; therefore, to ensure an accurate assessment, I suggest a thorough gait evaluation using slow-speed filming performed by a trained professional.

Identifying shoe type
Just as the foot functions differently based on its unique structure, a shoe also functions differently based on its design. Conveniently, shoes are classified into three categories according to their structure and function, and are called cushion, stability, or motion control shoes. When looking at the bottom of the shoe, the cushion-style shoe has a curved appearance from the heel to the toes. Its midsole will have one continuous color and a softer, flexible heel counter. A stability shoe will have a semi-curved shaped, a dual density midsole, which appears as a different color from the rest of the outsole, and a reinforced-sturdy heel counter. The motion control shoe will have a straight shape to it, a dual density midsole, and a rigid heel counter.

Matching foot type to shoe type
Figure 3 can help you determine which shoe is best for your type of foot. As the chart shows, I suggest a motion control shoe only for pronators who are of significant stature or weight. The majority of pronators will do fine with a stability class shoe.

Because the information provided here is little more than a crash course in shoe type identification, you can go to www.roadrunnersports.com or Runner's World magazine for the shoe manufacturer's classification of their running shoes. Also, most sales associates at reputable running shoe stores have access to the specific classification of the shoes they carry.

Daniel Kraushaar, PT, CSCS
Columbus, Georgia

References:

  1. Perry J. Anatomy and biomechanics of the hindfoot. Clin Orthop. 1983;177:9-15.
  2. Rodgers MM. Dynamic foot biomechanics. J Ortho Sports Phys Ther. 1995;21(6):306-316.