Last month I was on an easy 4-mile run when I noticed a weird ache in my heel. I’ve had my fair share of running injuries —from Achilles tendinopathy to hamstring issues to stress fractures—but this wasn’t anything I’d felt before.
I freaked out for a second, then did a little mental math. I don’t keep careful track, but based on when I’d bought them in relation to my last race, I figured my trusty Brooks Adrenaline running shoes might be a little past their prime. I altered my route home to swing by my local running store.
When I put on the new pair the next day, I felt like I was running on clouds. Heel pain gone, problem solved—why did I wait so long?
Of course, this wasn’t the first time I’ve had this experience. I pretty much always wear running shoes until something starts to feel weird before replacing them. After all, I pay $100 (or more) for them—I want to squeeze out every last quarter-mile!
But of course, I also don’t want to go through the pain, anguish, or expense of yet another running injury. “A new shoe is always cheaper than a doctor’s visit,” Chicago-area podiatrist and athletic trainer Lisa Schoene, D.P.M., A.T.C. , tells SELF—she’s one of the experts I consulted to help me fine-tune my footwear process. Here’s what I learned.
Each stride you take when running puts three to four times your body weight onto your feet—and if your shoes aren’t absorbing enough of that shock, your odds of injury increase.
Yeah, that’s a lot of pounding. So shoe companies put ethyl vinyl acetate (EVA), polyurethane, or special proprietary blends of similar foamy materials in the midsole to soften some of the impact, explains Schoene.
Over time and miles, these foamy bits lose their resilience. “When the cushioning or support breaks down in the shoe beyond the level that your body requires with your running mechanics, all of that impact will go directly into your muscles and joints,” Ryan Mleziva, M.S., of InStep Physical Therapy & Running Center in Wisconsin tells SELF. (He has undergraduate and master’s degrees in kinesiology and manages two of the company’s four shoe stores.)
Those forces contribute to a type of injury called overuse injuries. Those are the aches that creep up gradually rather than come on suddenly—think shin splints, heel pain, runner’s knee, and tendinopathy, Schoene says.
Aside from the impact factor, broken-down shoes can change your gait pattern, Nikki Reiter, M.S., a British Columbia-based biomechanist and coach for The Run S.M.A.R.T. Project , tells SELF. “That places stress on structures within your body that aren’t necessarily accustomed to having stress imposed upon them,” she says. Presto—more opportunities to get hurt.
At least, that’s what these experts see with the runners they coach and treat—there isn’t much research on the topic, but what there is seems to back up these claims. One small study in the British Journal of Sports Medicine —only 14 men and 10 women—found runners did indeed change their gait as aging shoes lost their oomph. However, the study didn’t look at injury risk.
A 2003 study of 844 Canadian recreational runners found men in shoes four to six months old and women in shoes one to three months old developed fewer new overuse injuries than those in older sneaks. However, the authors say they were studying a wide range of factors, and note it’s hard to draw firm conclusions, since sometimes runners try to solve injury problems by switching shoes. To say for sure, scientists would have to do specific studies that honed in on shoe age and controlled for things like training plans and biomechanics that also influence the odds of getting hurt—studies that just haven’t been done yet.
Shoe manufacturers say to replace your kicks every 300 to 500 miles, but there are a lot of factors that play into how long they’ll last.
Now, I run a lot—usually six days a week, up to 55 miles or so. If you do the math, that means I have to buy a new pair fairly frequently. And in fact, I do find that it’s at about the three-month-mark where things start to go awry.
But setting aside the fact shoe companies have financial and legal incentives to give you a conservative estimate, there are a lot of other reasons that the mileage you get out of a pair of running shoes may really vary. “Some people are harder on their shoes than others,” Reiter says.
If you’re heavier, drag your feet, land on your heels (which most of us do), or run on hard pavement and roads, your shoes might wear out sooner. Faster runners whose feet spend less time on the ground, trail runners on soft surfaces, and those who choose heavier, squishier sneaker models with more foam to soak up the shock, may get more miles than average.
It’s not necessarily the end of the world to wait until something hurts to buy new ones.
In fact, this is what Reiter does and advises to her coaching clients. Pain anywhere above or below the knee—especially in your arches or shins—is a sign your cushioning system isn’t what it needs to be, she notes.
You can always buy an extra pair ahead of time if you see them on sale or if you notice the shoe company is discontinuing your favorite model. As long as you start using a new pair ASAP after you identify an ache, you probably aren’t causing yourself long-term harm if you wait for a warning sign, she says.
But, there are a few ways to keep track so you can replace your sneakers before having to deal with discomfort.
“Our goal is to always replace people’s shoes before that happens so you have more pain-free running days,” Mleziva says. As a general rule, he tells customers who are casual runners they can go about a year (even if you don’t rack up 300 to 500 miles in that time, the foam still loses its oomph). Seasonal runners who race a few times a year can go six months, while regular half or full marathoners can likely go three or four months before buying a new pair.
If it helps, you can log the date you bought your last pair in your phone, or even pull out the insole and write it inside the shoe with a marker, Schoene says. Many running apps and online training logs, like Strava and Garmin Connect , will track the mileage on your shoes if you input them when you buy them. Or you can buy a Mino, a device that fits inside your shoe to monitor each compression ( runmino.com , $15).
Even eyeballing your shoes can help. You can’t see when foam loses its squishiness, since the appropriately named midsole is tucked between the insole and the outer sole. But there are a few visual cues: Holes in the uppers, worn-out treads, and permanent creases on the foamy parts of the side panel are all bad news.
“If you take the shoe and you bend it at the ball of the foot where you push off and it pinches over and kind of folds right in half with a solid crease, that’s another indicator that the foam is compressed down beyond coming back,” Mleziva says.
No matter how you’re keeping tabs, try Mleziva’s smart trick when you think it’s about time for replacements. Buy a second pair and slowly transition, rotating between new and old every day or two. “When you can tell a drastic difference between your shoes and you know one pair is shot, you can eliminate it,” he says. Sold.
Finally, there are a few ways to actually make your shoes last longer.
All three experts agree: Run in running shoes, not cross-trainers or models made for another sport . If you haven’t before, head to a specialty running store in your area, where trained salespeople can take a look at your stride and make recommendations on the best shoe for you.
Ask to try on several different brands and models and choose based on comfort, not looks or price, Reiter advises. You don’t have to shell out $200 for good shoes, but expect to spend around $100—sure, it’s an investment, but it’s pretty much the only thing you absolutely need as a runner. Plus, you’ll get a lot more life out of a high-quality, well-fitting pair than one that doesn’t work as well with your biomechanics.
Also, keep in mind that even errands add strain to your shoes. Consider keeping one primary pair for running alone, and using some you’ve recently retired for walking or doing errands, Reiter advises. If you do wear them out and about and track mileage, make sure you’re adding a few weekly miles to your total—10,000 steps per day equal about 3 to 4 miles for most people, Schoene says.
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