On BOTH your body AND your running shoes
Similar to food, running shoes have a shelf life, whether we wear them or not. Shoe materials deteriorate over time, both with mileage and when they sit in your closet slowly breaking down. As a humorous thought, maybe running shoes should have an expiration date stamp on the material to prevent using ‘expired’ shoes.
Rotating Your Shoes
Research has shown that rotating your shoes has been proven to prevent injuries.
By rotating from model to model, you are allowing your strike pattern, middle stance and toe off, to change just enough to allow your body not to overstress the same muscles and joints. When running in the same model over and over, your feet get used to the same feel. Rotating through different pairs of shoes can allow the 200 different ligaments in the foot to be stretched and be engaged in different patterns of use.
A recent sports-science medical study actually showed that runners who rotated through 2 or more different pairs of shoes throughout the duration of the 22-week study had a “39% lower risk of running injury than those who almost always ran in the same shoes”. (www.runnersworld.com/newswire/study-backs-rotating-shoes-to-lower-injury-risk)
Much like the body needs time to recover and respond after long or difficult runs, your shoes do as well! The outsole of a shoe is made of high-density foam, which compresses after long periods of stress and pounding. It actually takes about 24 hours for the foam of a running shoe to fully decompress after either running or walking in them. By allowing them to decompress fully, you allow the shoes to provide the cushioning and support that you originally had out of the box.
My advice is to get more than one pair of well fitted running shoes and rotate through them. You will find that your stability improves and you have less frequent injuries.
Dr. Bruce Harris