Making the shoe fit: good design can help prevent injuries caused by an unusual stride

Nation's Business, Feb, 1986 by Richard J. Chapel

Americans love running shoes. Thirty million of us consider ourselves runners of some sort. A lot of mileage is being run up out there--and there are a lot of sore feet, ankles, calves and knees. Responding to the demands of joggers, runners and racers, footwear manufacturers are offering a multitude of designs aimed at improving comfort and reducing running-related injuries.

Designing and manufacturing running shoes has gone high tech. Shoe manufacturers have adopted biomechanics--measuring forces and motions in parts of the body--as the basis for running shoe design. There are shoes that offer motion control, supercushioning and ultra flexibility for racing and special needs.

According to Linda Berlinghoff, a spokesperson for the shoe company Puma U.S.A., Inc., "Running shoes have never been better made. Over the past few years, the trend has been to lighter shoes, but not at the expense of support."

There is a shoe for every foot. But finding a fitting solution to your running needs requires a bit of self-analysis and an eye for shoe construction.

Your foot is one heck of a shock absorber. Says Peter Cavanaugh, professor of biomechanics at Pennsylvania State University and author of The Running Shoe Book: "Forces up to three times the body weight are applied at different places on the foot. When you consider that impact in combination with the various motions involved in a runner's gait, you have tremendous potential for strain."

The foot is designed to roll inward when it hits the ground. The experts call this "pronation." The foot hits first at the heel and then rolls, or pronates, so it can be as flat as possible on the ground before launching the body into the next stride.

Many runners overpronate. When this happens, the foot is loose and uncontrolled. It does not become the solid platform you need for a safe push off into the next stride. Overpronators may have problems with such injuries as shinsplints, knee strain, tendinitis, hip pains and joint inflammation. "That's why manufacturers have been seemingly obsessed with providing motion control," notes Cavanaugh. "The two key roles a shoe can play in this are shock absorption and stability. If you can control motion, you can prevent injuries."

Are you an overpronator? A way to check yourself out is to stand on cement with bare wet feet. A runner with the desired rigid foot motion will make wet spots at the heel, the toes and outside edge of the foot with a dry arch space. The pronator (often associated with flat feet) will usually show a wet spot in the arch area. An underpronator will barely show an outline of the outside of the foot.

Once you have an understanding of your particular gait, running shoe selection becomes a matter of speaking the shoemakers' language. You will hear shoe salespeople talking about various kinds of lasts. A last is the foot-shaped platform on which the shoe is built. Basically, it controls the stiffness and curvature of the sole.

"Board" lasted shoes offer stiffness and stability with less shock absorption capability. "Slip" lasted shoes are constructed like moccasins. These are more flexible and offer better shock absorption, but less stability. Combination lasting is catching on, and it makes sense. It offers needed stability (stiffness) in the rear foot and flexibility and cushioning in the front foot area.

According to Al Gross, research and development consultant for Converse Rubber Corporation, high technology has had its greatest effect at the midsole, the cushioning material between the upper and the sole. "We're using advanced multiple density materials to force the foot to fall properly in place along the midline of the shoe," Gross says. "Multidensity materials provide stiffness on the outside for control and supercushioning in the middle for comfort." It may sound complicated, but most feet have no trouble recognizing superior comfort.

Cavanaugh says that selecting the right shoe is especially important for the inexperienced runner. "Beginners need the best shoes they can get," he says. "They aren't in a position to judge precisely what kind of shoes they need, so they should avoid sacrificing foot protection for price." According to Cavanaugh, good shoes, featuring biomechanical designs, start at about $40, but the ultimate judge of suitability is not just a matter of construction. It is fit.

Look for flexibility in front, sufficient stiffness in the heel to keep your foot stable and centered, and good shock absorption.

Feel for snugness in the middle and rear where stability is key, but go for room at the ball of the foot. If your feet are cramped here, you won't get enough lateral support when they spread under impact.

Also, you should feel the arch pressing against the underside of your foot to prevent muscle fatigue. Test the cushioning by jumping. Finally, check the heft. You want a lightweight shoe, but not at the expense of stability and cushion.

Selecting the right shoe seems like a lot of effort, buy you can be sure your feet will thank you for it. A knowledgeable and patient approach will enable you to take shoe shopping in stride.