Why Knee Injury Rates From Running Haven’t Budged Over the Last 40 Years
When I recently visited Brooks Running's HQ in Seattle, I learned two major statistics about this particular affliction: Its rates have completely plateau'd over the last 40 years and it's the most common injury sustained on the run. And the why isn't so clear.
In attempt to find an answer, I took a deep, deep dive through past research conducted on the subject and spoke to experts in the field. In the end, it was kind of a selfish endeavor, TBH. Because here's the thing: Once you've had a taste of the kind of euphoria that can come along with lacing up your shoes and hitting the trail/road/treadmill, the idea of one day leaving the sport behind because your knees hurt after running seems equally terrifying as the possibility of sustaining the injury in the first place. Below, experts weigh in on why knee injuries persist and every step you can take to run injury-free through 5Ks, 10Ks, and marathons far in the future.
How running gait affects the knee and knee-related injuries
"Am I even doing this right?" is a question you've probably asked yourself on the run at least once or twice (um, per mile). After all, there's your arm swing to consider, the part of your foot that should be landing on the ground, and a million other tiny, technical factors. But according to Matt Trudeau, ScD, senior research scientist at Brooks Running, your body already knows exactly how it should be moving. The hard part is keeping it up for the extent of your mileage.
"The research has found that the knee is really important in running because one of the goals in running is to minimize shock to the head and to stabilize our vision," he tells me. "The knee’s really good at flexing and extending, but its range of motion is front to back. In the other planes of motion—so in rotation and side to side—it really places the knee in a vulnerable position." The natural way to move, the one your body knows by heart, is called your "preferred movement path" or path of least resistance. Trudeau says that sticking to it is your very best chance for safeguarding your knees from straying from their back-and-forth motion.
Ernest Isaacson, DPM, FACFAS, a New York City-based podiatrist agrees. "I train a lot of runners, and usually I say, 'Don’t try to change your gait because then you’re gonna mess up other stuff. Try to land where your body wants to land. Like, if you’re a mid-foot striker, then strike in the mid-foot. If you naturally land on the forefoot then that’s how you should land," he tells me.
Research backs both experts up. As Brigham Young University's Biomechanics team discovered in a meta-analyses of past studies, there's no decisive proof yet that total incidence of injury varies depending on foot strike types (i.e., heel, mid-foot, or ball of foot). Instead, injuries appear to arise when people consciously switch their gait into something their bodies wouldn't choose naturally. In other words, the idea that everyone should run pretty much the same way just isn't true, according to research. Instead, it's all about knowing thyself, er, knowing thy run gait.
To learn your made-for-you, preprogrammed pathway, you have a few options. First, certain shoe stores will video tape you running on in-house treadmills, then play it back for you in realtime. But the scientist notes that if seeing a physiotherapist or a podiatrist to talk you through how you move is an option for you, it's definitely in your best interest to do so. The why is twofer: First, you can never—and I mean never—know too much about your body. And second (this is what I've been leading up to this whole time), knowing how your body moves at its best will help you be aware of when your stride deviates into knee-hurting territory.
How to address the culprits that lead to knee pain
There are two main reasons why form degrades and ultimately leads to knee-related pain. Fatigue, on both a micro level (your individual runs) and a macro level (the wear-and-tear that happens over the course of your lifetime) is usually the culprit.
You probably already know that when you hit the wall during a long run or a sprint session, your muscles basically protest every single step. And if your muscles are no longer supporting you, then (you guessed it), all that assist work falls to your joints—including your knees. "We found that as you fatigued, as you might guess, your muscles become less and less able to support your knees," says Dr. Trudeau, whose team at Brooks is hard at work perfecting shoe technology designed to support you when your muscles inevitably lose steam.
Apart from ensuring your shoes have your back (knees?) when your runner's high wears off, Jeffrey Gilsdorf, MD, an orthopedic surgeon and sports medicine specialist with The Center for Advanced Orthopaedics in Maryland adds that cross-training and strength training are hands-down your greatest assets for keeping your knees (and all your other joints) operating at 100.
When people say colloquially that they've "blown out their knee," the physiological reality is that their knee became injured bit-by-bit, run-by-run until—at last—the whole joint gives out.
"Runners should focus more on helping to protect their knees," says the sports doc. "This can be done by focusing on strengthening the quadricep, hamstring abductors, and adductors, whether that is through exercise bands or weights." Pair this prep with a solid dynamic workout and you're giving your muscles their best shot at keeping injuries away.
Oh, and when you're deciding where to run, make sure you're switching surfaces up between the tread, road, trail, and beyond. "Running on the same type of hard surface day-in and day-out can be harmful. Training on a treadmill has also been known to be harsher on the knees," says Dr. Gilsdorf.
Apart from major injuries that might sideline you for weeks to years depending on their severity, the experts say you're constantly (yes, constantly) undergoing smaller, everyday wear-and-tear. "If you take, say 100,000 steps in a year, then that strain adds up. And at some point and time, your body isn’t able to repair itself sufficiently. That’s when the injury becomes more severe and pain results from that," says Trudeau. When people say colloquially that they've "blown out their knee," the physiological reality is that their knee became injured bit-by-bit, run-by-run until—at last—the whole joint gives out.
"In our practice, we have seen steady injuries caused by overuse," explains Dr. Gilsdorf, clarifying that types of injuries differ greatly by age group. "In young runners—from pre-teens to high school-age—we see more overuse injuries and early stress fractures around the knee. As they get older, we see more meniscus and cartilage tears as the risk for falling increases and arthritis has a greater impact," he tells me.
Before you sound the internal panic alarms though, just wait. I'm totally with you—knowing the causes and stats behind injuries can alter your perspective on the sport in general. But the important thing to remember is that we—all of us pavement-pounders—can only do our best with what tools we have available to us. That means cross-training, warming up, recovering properly, and checking all those other boxes that fall under the umbrella of "runner's self-care." If we're being honest here, much of what we love, much of what makes us feel truly alive is inherently risky. Running is no exception.
Here's the deal with four other types of running injuries. Plus, what to do next if you've lost your running mojo.
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