How to Know When Your Shoes Are Shot

The American Academy of Medicine and Rehabilitation reports that around 70 percent of runners get injured annually. That sounds like a lot, right? The majority of these injuries, though, don't require more than a little ice and time on the bench. It also turns out that many are completely preventable. While misguided training practices account for a number of them, one of the easiest injury risks to mitigate relates to what you're putting on your feet.

It was the fact of so many running injuries — and what causes many — that led to the invention of a new mileage-counting shoe gadget, the MilestonePod. The small pod that attaches to the laces of your running shoes uses an accelerometer to measure the position of the foot around 100 times a second, in turn logging your mileage.



The inspiration for the gizmo came from co-founder and retail running store owner, Zach Goren, who found himself constantly bombarded with questions from customers about when to replace running shoes. "We see a fair number of runners with pain and/or injury that often gets resolved with new shoes," explains Jason Kaplan, co-founder of MilestonePod. "As we began developing the product, it surprised us how many people answered the question of 'when do you replace your shoes?' with 'when my knee or hip starts hurting.'"

The rule of thumb for the life of a pair of running shoes has long been stated to be around 300 to 500 miles. For instance, if you're running 25 miles a week, your shoes might already be shot in three short months. If you're running 50 miles weekly, it'll probably be more like two months. Even with all the fancy technology built into shoes these days, landing at several times your body weight with each foot strike means your kicks take quite a beating.

Paul Langer, D.P.M., a Minneapolis-based podiatrist and clinical advisor for the American Running Association, agrees that worn-out shoes are often implicated in running injuries. For instance, when the upper fabric portion of the shoe is stretched, the foot can slip around in the shoe, increasing the chance of ankle sprains. Similarly, compromised traction, as a result of worn tread, can also lead to slipping and falling. What's more, Dr. Langer says, "Worn midsoles — because they tend to compress or wear in the areas of highest impact, such as the outside heel and forefoot — also increase the risk of injury because they wear out in an uneven manner, which tends to exaggerate whatever biomechanical imperfections the user may have."

To determine when you should replace your shoes, you must first consider the type of shoes you're wearing. "In general, the softer the shoe, the more quickly it will wear out," says Langer. "Stability and less-cushioned shoes, by their nature, tend to be more durable than soft or cushioned shoes because they are made from denser and more durable midsole materials."

Another consideration is the individual wearing the shoes. Due to everything from weight to gait to terrain preferences, some runners are simply harder on shoes than others. Over time, most experienced harriers develop a sixth sense as to when their shoes are on their way out. And it only takes one instance of pushing the shoes a few extra miles to teach a runner not to mess with their shoe-replacement cycle.

In addition to tracking mileage, which can give you a rough estimate of when to at least start paying attention to the potential breakdown of the shoe, Langer says you can often eyeball shoe age."The signs I look for are stretched or torn uppers, wrinkled or compressed midsoles, and any places on the outsole [tread] that have worn through to the midsole," he says.

If you're not sure whether your shoes are worse for wear, pop into your local running specialty store and they can help you decide if you can squeeze a few more miles out or not. While replacing shoes can be expensive, remember that it's almost always going to be cheaper than a weekly visit to a physical therapist.

When do you replace your running shoes? Have you ever suffered an injury because you waited too long to get a new pair?

—Mackenzie Lobby, Running Reporter

Mackenzie Lobby is a Minneapolis-based freelance writer and photographer with a master's in kinesiology from the University of Minnesota. She has run 10 marathons and is a USATF-certified coach and a self-certified local food hound. When not writing, she's running around the city lakes or picking produce at her local farmer's market. For more about Mackenzie go to mackenzielobby.com.

Photo courtesy of MilestonePod