What kind of feet do you have?

While that might seem like a strange question, knowing the answer is vital to choosing the proper running shoe and, in turn, reducing your risk of injury.

"It's best to get some professional advice when it comes to determining foot type," said Dr. John Cianca, medical director of the hp houston marathon. "It could be a podiatrist, an orthopedic specialist or a physical medicine expert -- somebody who has an understanding of how feet work during the running cycle and how your feet respond to the impact associated with running."

And there is plenty of impact.

A 160-pound runner puts more than 1,700 pounds of pressure on the legs with each stride, and it all starts in the feet.

There are three types of feet, according to Cianca, and knowing the characteristics of each will help you understand how to select the proper shoe.

Pronator: Feet roll inward too much when running. Over- pronators usually have very flexible feet. This can lead to knee and Achilles' injuries.

Supinator: Feet roll outward when running. Runners with this type of foot generally have high arches and rigid feet. This foot does not absorb shock as well as a neutral foot, potentially setting the stage for ankle problems and stress fractures.

Neutral: This type of foot has little, if any, motion- control problem.

"There are shoes specifically designed for each foot type, and if you don't match the right shoe to the right type, you can significantly increase your risk of injury not only in the feet, but up through the legs as well," said Cianca.

When purchasing shoes, seek out knowledgeable salespeople at an outlet that specializes in running shoes, Cianca said. And take along a pair of shoes you currently use for exercise. The soles can help the staff get an idea of how you wear the shoes.

"Comfort is the key to finding the right shoes," said Cianca. "Don't rely on 'breaking in' a pair of shoes. They should feel good the moment you slip them on."

Cianca is an assistant professor in the Department of Physical Medicine and Rehabilitation at Baylor College of Medicine in Houston. He is also medical director of the Human Performance Center in Greenway Plaza and a consulting staff physician at The Methodist Hospital. Cianca specializes in the treatment of sports-related injuries.

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