I have the flattest feet of anyone I know, so running is not something I do if I can avoid it. When it comes time to purchase running shoes, therefore, I simply walk into the store, pick out something inexpensive in my size, and walk out again.
The decision is far harder, I am told, for those who belong to that peculiar tribe of individuals who either don colourful clothing or take most of their clothing off to go jogging around Wascana Lake. These people take their shoes seriously.
So do the people who manufacture their shoes. Athletic footwear is a $1 billion-a-year business in North America alone. And every week another shoe company shows another expensive television commercial for yet another “breakthrough” in the art of shoe design.
Running shoes grew out of the 19th century’s canvas plimsolls, lightweight shoes with a leather sole surrounded by a decorative band of rubber. (They were named after the British politician who mandated the painting of load lines on the hulls of ships.) When the leather sole gave way to a sole made from a slab of rubber, the sneaker had arrived–but the soft rubber available at the time wore away much too quickly to be used by serious athletes. Sprinters could buy lightweight spiked shoes made of kangaroo leather, but marathoners still wore bulky shoes with stiff leather soles.
At the 1936 Olympics, some athletes (Jesse Owens among them) wore new lightweight shoes made by a German cobbler named Adi Dassler, who eventually formed a company called Adidas. But the first modern track shoe wasn’t introduced until 1962, by the Boston orthopedic shoe company New Balance. Its had a rubber wedge tucked between the sole and the upper at the rear of the shoe, raising the heel of the foot to relieve strain on the Achilles tendon.
A few years later, track coach Bill Bowerman, at the University of Oregon in Eugene, decided he could make a better shoe for his runners than the shoe companies could. Working with the Japanese company Tiger, he created a shoe with an upper made of nylon instead of leather or canvas, and, by experimentally pouring urethane into his wife’s waffle maker, created the waffle sole, which provided better traction. Bowerman’s shoe design was so successful, he formed a little company to promote it. He called it Nike.
The innovation that took Nike from Bowerman’s basement to shoe-making giant was the introduction of an extra layer of cushioning between the sole and the upper: the midsole. The runner’s foot strikes the ground with a force up to three-times that of his own weight, so extra cushioning was immediately appreciated.
Midsoles were originally made from rubber, but today running shoes use everything from encapsulated freon (Nike Air) to silicone gel. And the goal of the midsole has moved beyond mere cushioning to helping to control the motion of the foot, because the foot is far more important to a runner’s success than the shoe encapsulating it.
Each of your legs contains 30 bones and each foot contains 26. Ligaments bind the bones together and tendons link muscles to bones. These complicated assemblages act essentially as giant springs, storing and releasing energy as you walk or run. (Most shoes actually deaden the bounce of the foot somewhat, but due to road hazards, it’s unlikely we’ll see any great upsurge in barefoot running anytime soon.)
There are three energy-storing mechanisms in your foot. Your Achilles tendon, which connects your heel to your calf, gives your foot built-in bounce by stretching when you step down and relaxing when you step off. Your arch (which I don’t have) contains ligaments that stretch when you step down and relax when you step off, adding further bounce. And the fatty cushion at the heel of your foot acts as a shock absorber.
Two common foot-motion problems are over-pronation and supination. The normal running foot strikes the ground on the heel’s outside edge, then rolls inward, finishing with the weight on the inside edge of the forefoot. This is called pronation. If the foot rolls inward too much, that’s over-pronation, and flat-footed people like me tend to suffer from it, as do women, because they are usually wider in the hips than men. Researchers have learned to control it by stiffening the inner edge of the midsole. Supination is the opposite problem: not enough roll, instead of too much. Whereas over-pronators need a stiffer shoe, supinators need one that’s more flexible.
Today there are shoes designed just for basketball, just for squash, even just for aerobic dancing. There are even “runners” that are really “walkers.” Walking and running are quite different, physiologically speaking: walkers tend to sway from side to side, pushing off to the side with each step and shifting their centre of gravity over the supporting leg, while runners generally keep their body centered and swing their legs underneath. The walking foot’s motion is also different; it’s a slow roll onto the toes. Walking shoes play to these differences.
A shoe that fits just right maximizes the efficiency of the foot, not to mention maximizing comfort and minimizing blisters. “Pump” shoes let you pump air into bladders in the shoe to give them a perfect fit around your foot. But sometimes shoes fit too snugly; some modern shoes contain so many motion-control devices that the foot is held almost as though in a vise, so further engineering is taking place to enhance flexibility while retaining the cushioning, motion-control and other benefits.
Are this year’s shoes really that much better than last year’s, though? Flashy TV commercials to the contrary, probably not. The athletic shoe industry is one where science and technology run squarely into fad and fashion. Personally, I’ll content myself with just one rule of thumb when next I enter the store to replace my worn-out runners:
If the shoe fits, wear it.
