Your knees are a wonder. They’re the biggest, strongest, joints in your body, and most people use them almost constantly throughout the day to sit, stand, walk, jump, and bend. They bear 80% of your body weight when you stand still and 150% or more when you walk across the room. In a 160-pound person, that’s 240 pounds of force!
Age, injury, and repeated motion might damage your knees and lead to osteoarthritis, or OA, one of the most common types of knee arthritis.
In osteoarthritis, cartilage -- a smooth, slippery covering that helps the ends of your bones glide over each other -- slowly wears away. This allows bone to rub on bone. Typical symptoms like pain, swelling, stiffness, and loss of motion often get worse over time.
Normal wear and tear is a big part of the reason you get osteoarthritis, especially after age 50, but an injury, or constant lifting, jarring, or bending, also might cause or worsen the condition.
There are some things that might help protect your knees, or at least keep the damage to a minimum.
Lose Some Weight
Drop just 10 pounds, and you’ll take as much as 40 pounds of force off your knees. (The force depends on exactly what you’re doing.) That’s 40 less pounds of wear and tear on your knees every day, which could add up to a big difference over time. It may even lessen joint pain you had before the weight loss.
And it isn’t only the weight. Fat cells in your body release chemicals that can lead to inflammation, which is hard on your joints and linked to osteoarthritis. Less fat could mean less inflammation.
Losing even a small amount can help. Keep the weight off, and you’re much less likely to get arthritis later in life.
Still, not everyone should try to lose weight. Talk to your doctor about the best range for your size. One rule of thumb is to shoot for a BMI (body mass index) between 18.5 and 24.9. If you do decide to try to drop some pounds, work with your doctor to design a healthy weight loss plan that makes sense for your habits and lifestyle.
Exercise Your Knee
Far from harming your joints, exercise can help keep them healthy, as long as you don’t do the same motion too much, or overstress a joint (like the knee) that’s already injured.
Talk to your doctor if you have knee pain and you don’t want to make it worse. It may be better to avoid exercise that involves kneeling, bending deeply, or running downhill, which could be especially hard on your knees.
But while too much of the same motion raises your risk for knee pain, too little activity might also be bad. For example, people who can’t move because of surgery, injury, or illness actually start to lose cartilage in their knees and elsewhere from lack of use. So it seems you need at least some activity just to keep your knees in working condition.
And it isn’t just cartilage that benefits. Exercise helps strengthen and stretch the complex collection of muscles, ligaments, and tendons that form and move the knee joint. That helps keep it stable and moving in the right way. Exercise also helps with chronic inflammation, which is a cause of joint pain, and may help lessen inflammation linked to OA.
If you already have OA symptoms, exercise is the single best thing you can do (outside of taking medication) to ease pain and improve movement in your knee.
And don’t forget that exercise is part of a healthy weight loss program. When you shed those extra pounds, you take pressure off your knees.
So what kind of exercise should you do? All kinds!
- Aerobic activities, like walking, swimming, or rowing, could lower inflammation and boost your stamina so that you can remain active for longer.
- Resistance exercise, like weightlifting or lunges, strengthens muscles around the knee joint, like your hamstrings, calf muscles, and quadriceps. This helps keep the joint stable and prevent injuries. It’s also good for your core muscles to strengthen your knees.
- Stretching the muscles and connective tissue around your knee, like the iliotibial (IT) band, will help increase your range of motion.
Improve Your Technique
The most common cause of overuse injury in sports is bad technique. Even a small error or change in form in your golf swing or jump shot could have an effect. And good technique counts for simple things like lifting boxes and carrying groceries, too. Trainers, coaches, doctors, and physical therapists can keep you moving in the right direction.
Learn Some New Moves
You’ll avoid repeated motion injury to your knees if you vary your activities instead of doing just one. For example, you might jog on Monday, lift weights on Tuesday, garden on Wednesday, and play with the kids on the weekends. Or you could try something off the beaten path: Yoga combines strength, flexibility, and balance training, and adds meditation that’s good for mental health. It also seems to be as good for your knees as other types of aerobic and strength training exercises.
Whether you’re going to play a hot game of pickup basketball or help a friend move some furniture, it’s a good idea to loosen up your muscles, ligaments, tendons, and joints. One easy way is to march in place -- raise one knee then the other. All it takes is 5-10 minutes. That’s a small price to pay to avoid injury.
You may be excited about your new exercise plan, and that’s a good thing. But it’s best to take it easy. When you begin a workout you haven’t done before, your body needs a chance to get used to it. Then, over the weeks and months, depending on your sport -- weightlifting, tennis, jogging -- you can gradually add speed, distance, weight, or intensity. Check your body’s response to make sure you don’t injure your knees or anything else.
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American Academy of Orthopaedic Surgeons: “Arthritis of the Knee,” “Safe Exercise.”
American Council on Exercise: “What exercises are best to strengthen my knees?”
Arthritis Foundation: “Benefits of Weight Loss,” “Exercising With Osteoarthritis,” “Benefits of Exercise for Osteoarthritis,” “Marching in Place,” “Osteoarthritis Causes,” “Osteoarthritis Symptoms,” “What Is Osteoarthritis?”
Harvard Health Publishing: “10 tips to prevent injuries when you exercise,” “Age-proof your knees,” “Why weight matters when it comes to joint pain.”
Rush University Medical Center: “5 Tips for Preventing Knee Pain.”
Journal of Anatomy: “Exercise and osteoarthritis,” “The effects of exercise on human articular cartilage.”
Brain, Behavior, and Immunity: “Inflammation and exercise: Inhibition of monocytic intracellular TNF production by acute exercise via β2-adrenergic activation.”
Journal of Exercise, Sports & Orthopedics: “Osteoarthritis -- Why Exercise?”
Journal of Orthopaedic & Sports Physical Therapy: “Knee Injury Prevention: Exercises to Keep You From Getting Sidelined.”
American Orthopaedic Society for Sports Medicine: “Overuse Injury.”
Mayo Clinic: “Overuse injury: How to prevent training injuries,” “Yoga: Fight stress and find serenity.”
Rheumatology International: “Managing knee osteoarthritis with yoga or aerobic/strengthening exercise programs in older adults: a pilot randomized controlled trial.”