Are You Killing Your Knees?

Little bad habits could be quietly destroying this important joint

When was the last time you skinned your knee? It's probably been a while since you experienced this commonplace ailment of rough and tumble youthful times. But even if your grown-up ways have made frequent knee scrapes a thing of the past, your habits in adulthood could still be damaging your knees. The only difference now is that the damage may be a little harder to see.

We put an enormous amount of mechanical stress on our knees on a daily basis. And, typically, the knee is designed to take it. However, certain bad habits could be shortening the life of your knees and opening the door to chronic pain and disability.

The way you stand, walk, and move can have a tremendous impact on the health of your knee joints. Taking time now to evaluate some basic choices, such as your stance, your shoes, and your level of overall health and fitness, may help you side-step debilitating knee conditions like osteoarthritis and help keep your knees healthy, inside and out.

Ask yourself the following five questions and find out if you're being nice to your knees.

1. How much weight are you carrying?

Your knees bear the brunt of your body weight, so it's crucial that you maintain a healthy body mass index (BMI). Every extra pound you carry adds up to 3 pounds of pressure on your knee joints when you walk, and 10 pounds when you run. So, if your BMI is 25 or more, you may be compromising the health of your knees. In fact, obesity is one of the biggest risk factors for developing osteoarthritis because it speeds the breakdown of cartilage. Dropping extra weight -- particularly body fat -- may be the single most important thing you can do to reduce the risk of developing a serious knee problem. In a study reviewed by the National Institutes of Health, overweight people who lost an average of 11 pounds cut their risk of osteoarthritis in half.

2. Are you exercising?

Regular exercise is essential to maintaining knee strength. Without it, your muscles weaken, leaving your joints without ample support and leaving your muscles, bones, tendons, ligaments, and joints vulnerable to misalignment.

Your best bet is to choose activities with a low risk of knee injury. A knee injury can double the risk of developing osteoarthritis. Daily moderate exercise is much better for your joints than occasional strenuous exercise. Focus on low-impact activities that build stamina, strength, and flexibility, such as yoga, walking, biking, swimming, and weight lifting. These types of exercise can help enhance circulation, improve your range of motion, and build the muscles that surround the knee joints. One study revealed that a relatively small increase in quadriceps strength (20%–25%) can lead to a 20%–30% decrease in the chance of developing knee osteoarthritis. Aim for a minimum of 30 minutes of exercise on most days of the week.

Knee-Friendly Exercises

• Water workouts provide low-impact resistance and add a strength-training aspect to aerobic exercises such as walking or jogging.
• Tai chi can help increase your range of motion, lengthen your muscles, and make your ligaments and tendons more resilient.
• Isometric exercises and yoga strengthen core body muscles as well as leg muscles that support the knee.

3. Are you overusing some muscles and joints?

Staying active is one of the best things you can do to protect your knees, but you should avoid repetitive strain on muscles and joints. For example, repeatedly engaging in the same activity -- whether for work, recreation, or exercise -- may loosen tendons or damage cartilage and eventually lead to injuries and possibly even arthritis.

Determining if you are overusing a joint requires listening to your body. When you feel pain or discomfort during or after exercise, household chores, or other activities, don't ignore it. Take a break and consider ceasing the activity altogether until you can perform it without pain. In the meantime, stay active by focusing on other activities that do not stress the injured joint. If the pain does not go away in 2 weeks, see your healthcare provider.

To help avoid overuse injuries, spend 5–10 minutes warming up before you exercise and another 5–10 minutes cooling down afterwards.

4. Is your body properly aligned?

Just as driving a car when the wheels are out of alignment causes the tires to wear irregularly, the same principle holds true for your knees. If your body is not properly aligned, your muscles, joints, and ligaments take more strain than they are able to endure healthfully.

Here are some general principles of correct standing posture:

• Your back is straight. Don't slump forward at the shoulders or waist.
• Your knees are slightly bent - they should not be locked.
• Your abdominal muscles are tight - gently suck in your stomach.
• Your head is centered over your body. Check yourself in the mirror from side to side.
• Your weight is evenly distributed between your feet. Do not jut one hip out to the side.

A physical therapist can help you assess your biomechanics and teach you proper standing, sitting, walking, running, and lifting techniques that can help spare your joints from extra wear and tear.

5. Are you wearing the right shoes?

Shoes that cause your body weight to be unevenly distributed place extra stress on your knee joints. In addition to avoiding obviously uncomfortable or impractical shoes that can throw your stride off and stress your knees, you also should consider a visit to a specialty store if you have special anatomical considerations. As they say, nobody's perfect. Flat or rigid arches, uneven leg length, and bowed legs are fairly common in the general population, and each can contribute to an awkward stride and put pressure on your knees. Consider purchasing at least one of your main pairs of shoes or sneakers at a specialty store where the staff can advise you on which shoes provide the appropriate support for your foot and body type. Before you go, consider a visit with a podiatrist. He or she can help diagnose any additional foot concerns, such as overpronation or supination, and prescribe orthotic inserts that go into your shoes and correct your gait.

High-heeled shoes might add to the risk of osteoarthritis or other knee problems: A Harvard University study found that women who wear high heels have stress across the part of the knee where osteoarthritis usually develops.

Be Good to Your Knees Now

Arthritis of the knee is common, but it is not necessarily an inevitable consequence of aging. Taking care of your knees now will cost you a lot less time and effort than rehabilitating them down the road.