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    Knee Friendly Fitness

    By Cinder Ernst–

    Today I’m going to give you some guidelines for taking care of your knees while you’re working out in the gym. If you have a specific knee injury, get some help from your medical provider, especially a physical therapist, and go from there.

    I have learned all of the information presented here during the last three decades of my personal training career. Some has come directly from professional trainings I’ve attended, some from physical therapy (mine and others’) and some from my own experience. Everything is a guideline. Nothing works for everybody. You have wisdom in your own body, so pay attention as you go and follow your instincts. If a small voice says, “That’s enough,” or, “Not that,” then stop. There is always another option.

    With the above in mind, let’s get started by learning a few useful knee-friendly fitness terms.

    Open Chain and Closed Chain Exercises

    Open chain leg strengthening exercises are ones where your foot is not in contact with a surface while you use your knee joint. Open chain exercises are riskier on your knees. Examples of open chain exercises are leg extension and hamstring curl machines. I never use the leg extension machine unless it has been prescribed by my client’s physical therapist. The leg extension machine causes a sheering force to be exerted on the knee joint. Hamstring curl machines do not carry the same risk (no sheering force), and hamstring strength is important to knee health so have at it.

    Closed chain exercises are ones where your foot contacts the surface. Leg presses, squats, get ups, step ups, lunges, bridges and single leg bridges are examples of closed chain leg strengthening. Closed chain exercises are generally safe, but only if, and it’s a big if, you adhere to two important alignment guidelines:

    1. First, be sure your knee is tracking directly over your ankle, and not rolling in or out. Look in the front mirror to see that your knee is lined up.
    2. Second, follow the 90-degree rule. The 90-degree rule is always to keep the angle of your thigh to lower leg at 90 degrees (or more open). That means your knee stays over your ankle, and not over your instep or toes. To keep the 90-degree rule during a squat or get up, you will need to engage your core by bringing your front ribs towards your back ribs, then stick your butt out as you bend your knees. Try this while looking in a side mirror and notice when your knees get too far in front of your ankles.

    Cardio Machines Safest for Your Knees

    I will give you some general rules about what cardio machines are considered less risky, but what is most important is how you feel. Pay attention to the voice inside you.

    Treadmill: The treadmill can go either way in knee friendly fitness. On the one hand, there is a possibility of a sheering force as the belt moves in one direction and you move in the other. On the other, many people use it all of the time and are okay. My best advice it to mix up your cardio machines.

    Bike: The bike is the most recommended cardio machine for folks with knee problems. Upright or recumbent, pick what is most comfortable. Always start out with little or no resistance and give your knee joint a chance to warm up. Motion is lotion and non-weight bearing motion is great for your knees. If you are doing intervals or wanting to work harder, upping RPMs is safer than upping resistance. In other words, pedal faster and not harder.

    Elliptical: These machines are non-impact and weight bearing, making them a good combo for many people. There are many different brands and set ups, so experiment and see which ones feel good.

    The best cardio for your body involves mixing things up. Consider taking a walk in the park, too. Pavement or dirt is kinder to your knees than cement. Have fun and, again, listen to your body.

    Cinder Ernst, Medical Exercise Specialist and Life Coach Extraordinaire, helps reluctant exercisers get moving with safe, effective and fun programs. Her book, “Easy Fitness for the Reluctant Exerciser” (, is available in paperback and E-book. She specializes in fitness and rehab for plus-size clients, but her stress-free approach is suitable for all. Find out more at