Once upon a time--when life was simple--exercise was pretty generic, and so were your athletic shoes. To unwind, you shot a few hoops by the garage, tossed a softball over at the school or strolled down to your local mailbox. You probably wore a pair of $12 sneakers and never gave them a second thought.
Came the fitness boom and suddenly you learned that your old footwear just couldn't keep up. Maybe you started running 30 miles a week, practiced an hour of aerobics every few nights or joined a basketball or softball league. Walking, running, tennis, basketball and aerobics each involve different types of movements with their own distinctive patterns of stresses and strains. And so, because your work-outs got serious, you had to get a serious shoe.
In this case, a little consumer knowledge proved rather dangerous. Your need for the "right" shoe caused the shoe industry to make lots of models, not only differentiated by sport but often by the kind or level of activity you were doing in that sport. Runners had a choice of models made for sprints or ultramarathons, trails or road running, while aerobics fanciers could pick between models for high- and low-impact regimens, to name a few.
Currently, walking shoes and basketball sneakers are in, says Thomas B. Doyle, research and information director for the National Sporting Goods Assn. In 1988, while the overall market for sports shoes rose only 7% to nearly $3.8 billion, sales of walking shoes jumped 47%, and high-tech basketball shoe sales grew by 34%.
Today, however, the sports medicine, biomechanics and shoe-manufacturing communities are divided on a number of fronts. In large part, the controversies are due to an overall lack of knowledge on exercise biomechanics and its relationship to sports injury. Shoe design remains more art than science, although the guesses are becoming more educated.
One source of disagreement is the current back-to-basics movement, which is fostering the return of the generic athletic shoe (one that bears little resemblance--in look or price tag--to those $12 sneakers of the past). Part of this movement arises from the growing realization that specializing in a single sport isn't necessarily healthful, much less fun. "We've been looking at the fitness boom for years," says Tom Clarke, Nike marketing vice president, "and we've observed that people are becoming much more inclined to do a different number of activities to be fit."
However, this trend is also a reflection of the growing confusion over just how injury results from exercise. Here again, a little too much knowledge--in this case, on the part of researchers--has been dangerous. Sure, laboratory techniques have improved markedly and there is a growing body of data that is getting more sophisticated all the time. But are the data reliable? How can you truly gauge the impact of jumping, for instance, if no two jumps are alike? On the other hand, does the very act of gathering data--for instance, instrumenting a subject or asking him to land on a special device that records the force--affect the way a person jumps?
Increasingly, the answer for consumers seems to be: When in doubt, wear what's most comfortable.
Enter the cross-training shoe. "We were the first company to say that people who are concentrating in any particular sport need to buy a specialized shoe," says Nike's Clarke, himself a biomechanics Ph.D. But about two years ago Nike changed gears and premiered the cross trainer, a shoe for everyman, and subsequently turned the market upside down.
The cross trainer is especially targeted toward health club members who enjoy a variety of forms of exercise. "The typical cross-trainer (user) is a person who plays some racquetball, runs two or three times a week, maybe takes an aerobics class or lifts weights," Clarke says. Yet, he adds, such diverse activity is forcing people to make compromises that could be painful. "You have to be realistic and understand that these people generally don't buy different shoes for each sport," he says. "Chances are, they own tennis shoes, which is reasonable for racquetball but not for running."
The cross trainer combines the cushioning of running shoes with the firm foot support of basketball shoes. According to Clarke, the breakthrough that made the cross trainer possible was the "foot-frame," an extension of the midsole up the sidewalls (or upper) of the shoe--in effect, providing some of the support of basketball shoes but without their weight or stiffness.
Cross trainers are the most controversial development in the athletic shoe field. They are at best a half-baked compromise, according to La Jolla podiatrist Dr. Joseph Ellis, who happens to consult for Asics-Tiger, one of Nike's competitors. "The cross trainer is like a leisure suit," he says, "which is neither for leisure nor a suit."