What Exercises Are Harmful to the Knees?

Sitting on your heels with your knees bent overextends the knee and can cause joint problems.
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The American College of Sports Medicine recommends regular exercise, but not every exercise is right for your body. Some exercises put too much strain on joints, such as the knee. If you already have knee problems from an injury or arthritis, doing certain exercises can cause more damage and increased pain. However, this does not mean you should avoid exercising if you have knee problems, you just need to choose your exercises wisely.

Exercises to Avoid

    Certain exercises place too much stress on the joints and ligaments in your knees. Do you bend over to touch your toes while keeping your legs straight? Doing this actually places an unsafe stretch on the ligaments and joint capsule in the knee. Exercises like deep knee bends cause hyperflexion of the knee. This is when a joint goes past its normal range of motion. Avoid exercises like seated leg extensions at the gym because, according to physiologists from the Mayo Clinic, this machine places too much torque on the knee joint because the resistance is located at the ankles. As far as aerobic exercises, running and other high impact movements that are similar to climbing stairs cause the most stress to the knee.

Knee-Friendly Alternatives

    To avoid hurting or stressing your knees, mix some knee-friendly exercises into your workout schedule instead. For example, when you're stretching and trying to bend over to touch your toes, keep a slight bend in the knee. Or instead of those deep knee bends, try a lunge. To work your quadriceps, try straight-leg raises from a seated position on the floor in place of leg extensions. For cardiovascular exercise, walk instead of run. You may even want to trade in your tennis shoes for flippers as swimming and water aerobics offer a workout with less impact on the knee joint.

Exercises to Strengthen the Knees

    The Arthritis Foundation recommends regular exercise to help maintain joint range of motion and muscle flexibility. For the knee, exercise also helps relieve joint pain. To gain maximum benefit from working out for your knees, focus on exercising the muscles that support the knee — quadriceps, hamstrings, calves, abductors, adductors, gluteus mediums and gluteus maximus. Regular stretching exercises for these muscles — hamstring stretch and quadriceps stretch — increase flexibility and range of motion. Strengthening exercises like calf raises, hamstring curls and side leg lifts help to make the muscles strong.


    Before starting an exercise program for your knees, consult a physician or a physical therapist to discuss existing medical conditions. Begin exercising slowly and gradually increase as you are able. While exercising, you may feel tension in your muscles but you should never experience pain. If you do, stop the exercise immediately.

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