Remember the days when athletic shoes were called "sneakers"? Constructed with simple rubber soles, they provided neither style nor support and were cheap.

Today consumers are faced with a mind-boggling array of choices. They must determine which brand is best -- Avia, Nike, Reebok or Adidas to name a few -- which type of shoe is needed -- aerobic, running, walking, cross-training, tennis or basketball -- as well as what works better as a shock absorber: gas, gel, foam or air.

Sneakers have gone high-tech with prices to match, a fact that has helped to make athletic shoes an $11.4 billion industry. Nike's Air 180 running shoes retail for $125. Avia's Arc 610 aerobic shoes sell for $79.95. Some shoes are priced as high as $170.

Athletic footwear can be divided into two groups: running shoes and court shoes. In each case, the motion of the foot is different. Runners need shoes that absorb repeated pavement-pounding shock. Without cushioned shoes, they experience heel bruises and shin splints, according to Joe Ellis, a podiatrist in San Diego.

In court sports such as basketball, volleyball or tennis, there are more quick start-and-stop movements, as well as pivots and lateral motions of the foot. Ankle sprains are a common injury in court sports, says Ellis.

Weekend exercisers may not seriously participate in a single activity but instead may lift weights or jog and play tennis occasionally. Do they really need a different pair of shoes for each sport?

No, says Barry T. Bates, a professor of biomechanics at the University of Oregon, who studies motion and its effect on people.

"Cross-training shoes are the industry's attempt to design a shoe that will function in more than one environment with real success," he says. Such shoes are built with cushioning and heel protection for runners, while still providing the flexibility needed to play a game of basketball or tennis. Cross-trainers can even be worn during an occasional aerobics class, Bates notes.

"If you are engaging in multiple sports, a cross-trainer is the way to go," says Wayne Spinney, a product marketing director for Avia Group International. "You can get good cross-training shoes for $50 to $70. It is ludicrous to spend $170."

Only one atheletic shoe in five is purchased for sport, according to Harvey Lauer, president of American Sports Data Inc., a New York research firm. "That means four in five shoes are never sweated in at all," he says.

Whether the shoe is purchased for fitness or fashion, there are some guidelines to follow. Marlene Adrian, a biomechanics researcher at the University of Illnois, recommends: Buying from a brand-name company for adequate structure and support. Making sure there is enough room to wiggle the toes. Trying out the shoe in the store by running, jumping or lunging in it.