THE BRONX - For those who suffer from back or knee pain, the problem could be caused by the shoes you're wearing.

"A lot of times people run in their shoes for much longer than they should, so you lose that cushion and support. A lot of injuries are related to bad footwear or old footwear," says John Davis, of Jack Rabbit Sports Inc.

The shoe specialists at Jack Rabbit Sports say that their staff has a deep knowledge of the footwear they sell and know how each shoe fits.

When selling shoes, each salesperson gets a background from each customer. They also make them stand up and inspect their arches. Based on the information, they can determine which category of shoe to recommend to the customer.

They do warn that the average life span of a shoe is about 450 miles, which typically equates to about six to seven months.

Also, if you start to get aches and pains that you never had with a shoe, it's a sign that the shoe is past its prime.