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These four strategies will help reduce strain and impact and let you keep running as you deal with knee issues.
DECEMBER 8, 2020
While studies are clear that running doesn’t damage knees, it strengthens them, runners often end up with sore knees from a variety of maladies. Persistent or increasing pain calls for a doctor’s visit, but often we have to deal with low levels of pain when rehabbing from injury or managing chronic problems like runner’s knee, cartilage degeneration and incipient arthritis. Runners with sore knees often need to strengthen supporting structures in their stride, from hips to hamstrings to feet. In addition to strengthening, try these four strategies to help you keep running by lowering the stress and pain on your knees.
1) Lower Your Heel Choosing a shoe with a lower heel height can reduce the forces on your knee and often relieve pain. We started paying attention to heel-to-toe drop — the difference in height between the heel and the forefoot — during the minimalist movement. Those who espoused minimalism claimed that a lower heel drop was more natural and inherently better. Simon Bartold, podiatrist, biomechanical researcher and shoe design consultant, argues, however, “There’s no such thing as good or bad drop, it is how you use it.”
A shoe’s drop changes your center of mass over the shoe. “If you have a higher drop shoe, it is going to shift your center of mass forward, and if you have a lower drop shoe it’s going to shift your center of mass backwards,” Bartold explains. That backwards shift reduces the rotation going through the knee joint, and thus reduces the load on the knee. Bartold points out, however, “You have to put the load somewhere else. You can reduce the load at the knee, but you will increase it at the ankle joint.”
Understanding this allows you to move the stress around to spare areas where you are weak. “If you’ve got somebody who has chronic anterior knee pain, it would be completely sensible to put them in a lower drop shoe, or even get them to do some barefoot training, providing you monitor what is going on at the ankle,” Bartold says. Whatever change you make is going to stress your body in a new way, so make gradual adjustments to avoid replacing one injury for another. You might at first choose a shoe with an 8mm drop rather than 12mm, or, you could only run a few miles a week in a low-drop or zero-drop shoe to start. As you adapt to your new shoes, your stride may subtly change as well, which may further reduce knee stress. 2) Take Quicker Steps
Another way to manipulate forces is to play with your cadence, or how many steps you take each minute. Studies have shown that increasing your step rate can substantially reduce the load on your hips and knees, including lowering peak braking force by 15 percent.
Don’t get caught up in the idea that there is a perfect cadence for everyone, often cited at 180 steps per minute, or even that a faster cadence is always better. “The idea that there is single optimum for all flies in the face of the science,” says Bryan Heiderscheit, a leading researcher on cadence at the University of Wisconsin. Your best cadence will depend on your speed, flexibility, strength and stride mechanics, and most of the time you can trust your body to optimize it.
It’s when you have a problem, like knee pain, that Heiderscheit recommends playing with your cadence. “Whatever your turnover is, measure it at a particular speed, then go for trial a run with an increase of 5 to 8 percent, and see if it changes your symptoms,” he says. “If it does, great, use that strategy for a period of time to get those symptoms under control.” The new pattern will require more effort, so it doesn’t have to be permanent, although you may find the new turnover becomes your new default.
You can actually count how many steps you take per minute, but far easier is to monitor your cadence using a smart watch or fitness tracker. Most of the time you can increase turnover just by focusing on stepping faster. Many find it easier to focus on swinging their arms quicker, and their legs follow the rhythm.
3) Run Uphill Anyone with gimpy knees quickly learns that they hurt less when we’re going uphill. Unfortunately, what goes up must come down. Unless, however, you take your run indoors, where you can crank the treadmill up to one continuous hill for as long as you can handle it. Why does running uphill hurt knees less? “An inclined surface moves the foot contact closer to the body,” says biomechanical researcher and physical therapist Jay Dicharry. “This changes the load through the pulleys and levers in your body — your joints — to lessen load at the knee and shift a bit more to the hips.” Essentially, the grade ensures that you don’t reach too far forward, and requires that higher cadence at the same speed.
Those changes in stride also alter muscle recruitment. “When you increase your incline, two things happen,” says exercise physiologist Jill Drummond. “Your stride is improved, and posterior-chain muscle activation increases — all of that works to protect your knee.” Drummond cites a 2008 study from AT Still University that showed that at 0% incline, hamstrings, glutes and calf muscles are activating at about 20%. When at 27% incline, however, glutes are 100% active, hamstrings 73%, and calves at 80%. Not many of us are going up to 27% — although jumping on an incline trainer that can create that kind of slope is a great option for getting in a quality workout when your knees won’t let you run. The same study showed that heart rates when walking at 2mph at a 24% incline are higher than heart rates when running at 6 mph — 10 minutes per mile — at a 0% incline.
If you can run, however, how steep should you ramp it up? “The key thing is to experiment for what works for you,” says Dicharry. “If you use too high of an incline, it will slow you down too much. When you slow too much it increases time on ground and decreases the bounce in your step — and that increases muscle stress. You want enough of a hill that your joints feel better but you still feel some bounce in your step. Typically, the sweet spot for this is between 3–6% grade for most folks.” If you find you knees need a steeper grade than you can maintain, Dicharry recommends making it an interval workout, something like 4 minutes run/1 minute walk, keeping the total run time the same. 4) Run With Wheels When you want to get in a solid aerobic workout and avoid all impact, it makes sense to get on a human-powered wheeled vehicle. But while a bike has some cross-training benefits, it produces a significantly different mechanical challenge, with a different level of required effort. That means that while you can build cardiovascular fitness you’re not improving running specific strengths and skills, plus, cycling requires many more hours to achieve similar effects.
You can, however, more closely run with wheels on an Elliptigo or Stand Up Bike (SUB). Designed to mimic the running motion, the Elliptigo puts you in the same upright position and requires similar hip extension and glute activation as you drive backwards through the running-specific ellipse. Studies have shown that riding an Elliptigo requires a similar level of effort as running and you can maintain and build running-specific fitness and performance — including running economy and race times. The SUB and MSUB (Mountain Stand Up Bike) are less expensive and have a more traditional circular motion, but provide a similar no-impact, high-effort workout and core-building upright posture.
Runners of all ages, including many elites like Meb Keflezighi , incorporate Elliptigos into their training, and there have been some rather spectacular come-back stories of injured runners who used them while injured. Fifty-five-year old Brian Pilcher, for example, trained with an Elliptigo after hip surgery and knee pain sidelined him for months. Just weeks after being cleared to run again, he won the 5,000m and 10,000m national masters championships.
Ultrarunning champion Max King says, “ I find myself on the MSUB usually when I’m injured but I try to keep some cross training in even when I’m not. I find it is more specific to running than biking but it takes stress off my legs because there’s no pounding. Generally if there’s something painful on the run, I won’t feel anything spinning on the MSUB.” Coaches who use the two upright cycle options say runners needing to spare their knees should try each as they use somewhat different muscles. Kim Nedeau, trail champion, running coach and injury prevention specialist says, “Muscle recruitment on the long stride model is nicely balanced and does not dominate any one particular muscle group whereas the SUB is quad dominant and translates nicely to incline running.”