Your doctor told you that you need more cardio exercise, and you're not alone: According to statistics from the Centers for Disease Control and Prevention, only 53.1 percent of Americans engage in their recommended weekly aerobic exercise of 150 minutes per week.|
And for the 46.9 percent of us who aren't getting in that two-and-a-half hours, we're missing out on more than just sweat. With a little more than 20 minutes of movement per day, you can reduce your risk of heart disease, Type 2 diabetes, stroke and certain cancers, as well as reduce your risk of "all-cause mortality," or early death. And while you're alive, those 20 minutes can make you better at your job, too, making you more productive during the day and more satisfied by the time you head home.
If your knees are cranky or achy, though, 20 minutes per day can feel like an uncomfortable eternity. As it turns out, that's the case for a lot of us: Statistics from the CDC show that almost 20 percent of Americans experience knee pain, making it the second most common source of pain after
"I'd say maybe 30 percent [of new trainees say their knees hurt," Head says. A master trainer at Sport & Health in McLean, Virginia, and the author of "Not Another Fitness Book: A Memoir. A Manual. A Message for 49 Million Baby Boomers", Head works primarily with clients who are over 40. When they think of cardio, he says, they often say the same thing: "'I want to lose weight, but I don't want to run.' People don't want to run."
It's not just Head's clients that think "cardio equals running", either. One survey from 2013 found that pounding the pavement is still America's most popular form of exercise. But if you've got bad knees, watch out because runners get injured, and the knee is the most common place they get hurt. In a review of 17 different studies published in the British Journal of Sports Medicine, researchers found that between 19 and 79 percent of runners suffered injuries during the course of the studies, with knee injuries being the most common. And the older the runners were, the more prevalent the injuries.
Mike Boyle, owner of Mike Boyle Strength & Conditioning, says that many trainees don't realize the ground forces involved in running. Even slow runners put more than 1.5 times their body weight into the ground with each stride—and that's all on one leg. "If you think about running or jogging, you do about 1,500 foot contacts per mile. If you weigh 200 pounds, every step is giving you 300 [or more] pounds of force."
Running, then, Boyle says, may be the worst form of cardio if you've got bad knees. But if it's doctor's orders to get more cardio or you're working on your overall fitness, don't despair. There are many options that allow you to get your heart rate moving while keeping your knees safe.
Get your arms involved.
Riding a bike, Boyle says, "is a simple action that anybody can do. You rarely find someone who can't." But while using a spin bike or other stationary cycle eliminates ground contact and can be safe for the knees, it's still only working your lower body. Which is why his favorite cardio option, whether you have bad knees or not, are dual-action bikes, where both your arms and legs move simultaneously.
Why? Because cardio isn't about working your legs—it's about elevating your heart rate. And when using all four of your limbs at just 60 RPM, Boyle says, you can reach heart rates that are much harder to reach on a traditional bike.
Being able to elevate the heart rate easily also makes these dual-action bikes ideal for high-intensity interval cardio, Boyle says. In multiple studies, this type of cardio—where higher-intensity bursts are alternated with bouts of rest or low-intensity recovery exercise—have been shown to help burn more fat than traditional, steady-state cardio work. In one study from 1994, for example, subjects lost more fat with 15 weeks of intervals than steady-state exercisers lost in 20 weeks.
Get stronger side-to-side.
Most of our cardio work (and workouts in general), are performed front to back. We run or bike straight ahead, push weights forward in the bench press, perform walking lunges—all movements that have the body moving in a linear plane. As a result, many exercisers are weak moving side-to-side, which could put them at risk for injuries like an ACL tear.
These lateral movements and muscles can be strengthened. Boyle likes mini-band walks, where a small exercise band is placed on the lower legs, and trainees shuffle side-to-side in a controlled manner. But Head also likes to include a cardio component in this lateral movement for his over-40 clientele. While many of his trainees with knee issues may perform some cardio work on a knee-friendly recumbent bike, "We have to have an alternative, too," he says. He likes each of his clients to fight off boredom and add variety to their movement by having multiple cardio modes at their disposal. He adds to their side-to-side strength and mobility by making that alternate mode a lateral elliptical trainer.
Your gym may have one of these, and you don't even realize it: A lateral elliptical trainer (like the Bowflex LateralX) looks just like a regular elliptical machine. But once you've gotten going in the normal way, you can start to apply pressure from one side to the other to perform a more lateral cardio movement.
"It's entirely safe. The hardest part is getting it moving, because many people don't know how to direct their force. But once it clicks, the pattern is pretty natural," Head explains, comparing it to roller skating or speed skating. And unlike a traditional elliptical, on which it can be hard to reach a truly difficult effort, the challenge of this unfamiliar movement ramps up quickly. "Your quads burn out pretty fast. [When they're starting out,] I get people on and off it in about four or five minutes."
Before they get on, though, Head helps them work on hip hinging—an essential fitness component that involves getting their back, butt and legs in the right position so that when using this lateral trainer, their weight is in their heels and their knees are safe. To get into a hip-hinged position, imagine you're holding a box or a big bag of groceries in your arms in front of you as you stand straight, and you're going to close a door that's behind you using your butt. Bump the door closed with your bum—doing this will push your hips back. That's a hip-hinge position—butt back, back flat, knees slightly bent. When you're on the lateral elliptical, Head says, you'll want to be in this position to keep your knees safe.
If you're not sure if your gym has one of these machines, or if you need help getting that hip hinge right, just ask! Your gym may offer a free personal training session that can help you get the hang of this new cardio move.
Use strength work to get your cardio.
When looking to lose weight, strength training often gets pushed to the back burner in favor of the calorie-burning power of cardio workouts. Per the CDC, just 23.5 percent of Americans do 150 or more minutes of aerobic exercise per week and get in two or more strength sessions as recommended. But there's good news: You can get cardio from strength work—and it can be easy on your knees.
"When using a variety of strength exercises as interval training, you're working multiple muscle groups and distributing the work," says Mike Whitfield, a trainer and author of "Rise and Hustle". "If you think about traditional [cardio] interval training, you're using your legs and that's it. However, [with] a circuit of glute bridges, TRX rows and pushups using a fast tempo, you're working your whole body."
For an even simpler circuit that's safe for the knees, Whitfield likes to mix planks with an exercise called a "total body extension."
"The total body extension is great because it's a little less than a quarter squat. For most people, it's squatting beyond that quarter mark that becomes painful. This allows some quad recruitment without being 'invasive' to the knees," he says. "And because you're 'swinging' your arms up, you're recruiting other muscle groups, cranking up your heart rate"
To perform the move, stand with feet shoulder-width apart, knees slightly bent. Keeping your chest up, drive your hands back behind your glutes and bend your knees as if you're going to initiate a jump. Then explosively extend as if you're jumping straight up, bringing your hands up overhead into a full-body extension while coming up onto your toes without jumping. Return to start, and repeat.
To use this move in a heart-pumping cardio workout for beginners, Whitield suggests performing the move for 15 seconds, then resting for 45 seconds. Repeat this six times. If you're up for a real challenge, don't just rest: Perform 30 seconds of the total body extension, then do 30 seconds of a forearm plank before repeating.
Hey, wait a minute. I want to run!
That's okay, too! As with any exercise choice, your ideal solution is one that you enjoy and can do consistently without getting hurt.
"We have to look for things we enjoy. We're far more likely to do it long-term [that way,]" says Head. But, he adds, it's important to avoid activities that hurt and focus on strengthening ourselves to reduce injury risk and discomfort when doing the things we do enjoy.
People with cranky knees, Boyle says, are often weak in knee-dominant exercises, and need to stretch more often. To strengthen, he says, "You need to do some kind of squat. [For us,] that usually ends up being a basic, beginner bodyweight split squat."
To do this move, stand with your right foot about three feet in front of your left. Keeping your torso upright, bend both knees to descend until your knees both form 90-degree angles, with your front knee tracking over your toes. Press back to standing. Perform five to eight reps, then switch legs and repeat.
For the stretching, Boyle suggests doing so after a session of foam rolling at the start of your workout. To help with knees, he says, the traditional "heel to butt" quadriceps stretch is a great option. Once you can bring your heel up to your butt, focus on keeping your knees together so that your legs remain parallel during the stretch.
Bad knees should not deter you from being able to get your cardio minutes in and reap all the benefits of a balanced workout routine. With a few modifications and some clever substitutions, you can get your heart rate up without ever having to tie up your sneakers and run. Remember that the best workout routine is the one that you do and the one that benefits your whole body, just as it is, bad knees and all.