When it comes to running, wearing the wrong shoes for your feet is like wearing a bicycle helmet to play baseball. Having the right equipment matters.

Not all feet are created equal, and each foot type needs exactly the right shoe to prevent blisters and aches or worse.

Knowing how your foot hits the ground dictates what shoes to buy. Walkers and beginning runners tend to hit the ground heels-first, calling for heavy cushioning at the back of shoes. More experienced athletes run on the balls of their feet and need a shoe with substantial soles at the front of a sneaker.

Barbara Saia, 40, of San Luis Obispo, Calif., a marathon runner and Central Coast campaign manager for the Leukemia & Lymphoma Society's Team-In-Training, recruits volunteers to walk or run marathons. She counsels volunteers to seek help from shoe professionals before starting their training. "Most runners don't realize they're wearing the wrong shoes," she says. "Shin splints, pain in the knees and legs are attributed to the wrong shoes."

In addition to proper cushioning, identifying how an arch collapses as the foot rolls during each step, called pronation, determines the kind of support a foot requires. There are three types: overpronation, neutral pronation and underpronation.

In overpronation, when the foot hits the ground, it rolls and the arch over-collapses, making it unable to stabilize the body or absorb the step's impact. The best shoes for overpronators are usually stiff-soled, called motion-controlled, to reduce rolling.

In underpronation, also called supination, the arch does not connect with the ground. As a result, the impact of each step is limited to the outer foot, small toes and legs. Shoes that are best suited for underpronation have no added stability and encourage the foot to roll toward the arch, spreading the weight equally on the foot.

Neutral pronation is the most common pattern. As the foot rolls, the heel connects evenly to the ground, and the body's weight is supported while the step's impact is absorbed. Recommended shoes are medium-stability shoes with average cushioning and moderate arch support.

Greg Hind, 59, owner of GH Sports, cautions runners to understand their feet before shopping for shoes. At his San Luis Obispo store, he has a prospective buyer walk or run on a treadmill, recording the movements with a video recorder to analyze foot placement and arch height. After that, a customer knows exactly what type of shoe best fits their needs.

"The problem with making generalizations is that not all people fall into a specific category," cautions Hind. "Each runner is different and so are their needs. A running shoe has no break-in period. If there's something that doesn't feel right, it's probably not going to go away."