Several studies have shown that just walking down the street in heels can lead to everything from blisters and bunions to backaches and sprained ankles.

When wearing 2-and-1/2-inch heels, the women took on an unsteady gait. They'd land much more softly than is typical on their heel, and then the foot went flat. Then, they they'd put a lot of force on their toe in order to move the body forward to the next step.

An unsteady gait could lead to excessive muscle activity in the lower leg, which could precede a foot injury.

The study also showed that when barefoot, the women walked more confidently, placing more force on their heel.

The bottom line: Limit your use of high heels, especially if you have foot injuries or back problems. And certainly limit the height of the heel. Suggestion: A 1-inch chunky heel at most.

Flip-Flops Linked to Abnormal Gait

As comfy as they may be, flip-flops may also lead to abnormal changes in your stride, other researchers say.

There were reports that people who wear flip-flops for extensive periods alter their normal gait and experience lower leg pain.

Because they lack the support that a walking or running shoe provides, flip-flops should only be worn for short periods of time, "like when you go to the beach. They should not be your primary form of footwear."

Also, replace flip-flops every three or four months.

Jeffrey A. Ross, DPM, a clinical professor of medicine at Baylor College of Medicine in Houston, says, forget the heels and the flip-flops: Invest in a good running shoe instead.