April 5, 2020

The Impact of Running

When you’re “pounding the pavement” during your early-morning jog or after-work run, the pavement is pounding right back.

“When your foot hits the ground, the ground doesn’t bounce back like the Pillsbury Dough Boy and giggle. The ground has a rebound effect: it throws the load back at you,” explains Jenny Kempf, MPT, CSCS, a physical therapist with the UW Health Sports Medicine Runners Clinic. “The load can be anywhere from 2 to 2.5 times your body weight. For most people, that load isn’t that big of a deal. But your tissue will start to break down over time if the load is too much.”

So does that mean you’re destined for a bum knee? Not necessarily. A high load affects runners in different ways. “Increased load affects the weakest link in your body,” Kempf says. “For some people that’s ankle weakness, for some it’s hip pain or knee pain. It’s different for everyone.”

How you run can increase or reduce the impact on your body. But unless you’ve already been hurt, you may not even realize that your running style is putting you at risk for injury. “It’s such a fast movement and you’re on the ground for such a short time period that it’s hard for people to feel the ground reaction forces,” Kempf says.

Injury-Proof Your Running

Here’s what to know about how to adopt a more injury-proof running style:

If you’ve been injured, get a running injury evaluation. You can’t spot most running mechanics issues with the naked eye — they happen too fast. Instead, experts can use slow-motion video to analyze your stride. A video analysis, which can be covered by insurance if you’re recovering from an injury, will likely reveal how your running mechanics could be improved to prevent future injuries.

Or get a performance running evaluation to boost your speed and efficiency. You’ve most likely never seen yourself run and might be surprised by what you see in the video playback. “That visual feedback is really important for someone who doesn’t have an awareness of how they’re running or who has never thought about it when running,” she says. That data can help your clinician or trainer optimize your running mechanics to improve your efficiency and prevent injuries.

If you’re really serious about analyzing your running mechanics, you can opt for a state-of-the-art, three-dimensional computerized analysis that combines eight high-speed cameras with a specialized treadmill that can measure ground contact forces. UW Health’s Runners Clinic can also recommend running drills to help improve your strength and awareness of your mechanics.

Try a new approach. “The strongest predictor of a running injury is a previous running injury,” she notes. “If you’re injured, it makes sense to change how you run. Consciously changing your running style will feel weird at first, but you’ll get used to it. It takes most people three to four weeks of consistent practice to feel that change. Once you get used to the new running mechanics and your pain has gone away, it’s up to you if you want to return to your old running style.”

But sometimes the change brings immediate relief. “Many times in clinic, if someone is running with pain, and we make a change, we can reduce their pain right then and there, which is really cool because then we know we’ve found something that helps,” she says. It’s important to make a change in consultation with an expert — don’t just try what worked for a friend or spouse.

There’s no “right” way to run. “There’s no ideal running mechanic,” she notes. “Leg length is different, pace is different, body weight is different. A change that works for someone else may not work for you. No two runners are the same.”

Run at your own pace. It’s not a good idea to try to keep up with a taller running buddy. “Taking too long of a stride increases load to your body and increases stress to your knees,” Kempf explains.

Be mindful of the midline. If your foot strikes too far toward the other side of your body, it increases the load. Instead, try to run with your feet more spaced apart.

UW Health Services

Runner's Clinic

Sports Medicine

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