1. Warm-up and stretch before exercising. Warming up and stretching can help the knee joint in many ways, including increasing the circulation of the blood and lymph fluid into and out of joint structures and the adjacent soft tissues and ensuring that the muscles and the ligaments attendant to the knee joint are not too tight. As a result, tension on the tendons is reduced, and pressure on the knee is relieved.
2. Develop muscle balance. Strengthen the muscles of the lower body to reduce the amount of force that goes through the knees. Make sure that you maintain an appropriate muscle balance between the quadriceps and hamstrings (i.e., a 3-to-2 strength ratio is recommended) to provide an improved level of stabilization and strength for the knee joint.
3. Avoid doing too much exercise. Some individuals hurt their knees because of the overuse syndrome. Simply stated, cumulatively, they place excessive demands on their knees.
4. Avoid sudden increases in the intensity of exercise. Allow your body to gradually and progressively adapt to the demands that you impose on it. Doing too much too soon can injure your knees. Keep in mind that some actions that alter intensity level are not as obvious as others. For example, changing your approach to exercising (i.e., running hills instead of jogging on a flat terrain) may unduly increase your level of intensity.
5. Protect your feet. Your feet (particularly how and where they strike the ground when exercising) can have a profound effect on your knees. In this regard, two of the most meaningful actions you can undertake are to wear shoes that fit properly and provide adequate cushioning and to immediately take care of any foot problem (e.g., blisters) that occurs.
6. Vary the mode of exercise. Using several exercise modalities keeps you from repeatedly stressing the same bones and muscle groups, thereby keeping the orthopedic stress on your knees to a minimum.
7. Be conscious of possible load forces on your knees when choosing your exercise mode. Whenever possible, avoid engaging in an exercise modality that places unduly high impact forces on your knees (i.e., running stadium stairs, running downhill, etc.).
8. Use exercise equipment properly. Improper use of exercise equipment can cause knee problems. For example, if you exercise on a stationary bike, check the position of the pedal crank relative to the seat post. If the crank is not relatively close to the seat post, you will place undue stress on your knees while exercising.
9. Keep your weight down. Maintaining an appropriate level of weight can reduce the stress on your knees. Excessive weight can increase your risk of degenerative conditions, such as osteoarthritis of the knee.
10. Listen to your body. Pain is your body's signal that you may be placing too much stress on your knees. Reducing or stopping whatever is causing the stress is the primary step in ensuring that your actions don't lead to a more serious injury.
James A. Peterson, Ph.D., FACSM, is a freelance writer and consultant in sports medicine. From 1990 until 1995, Dr. Peterson was director of sports medicine with StairMaster. Until that time, he was professor of physical education at the United States Military Academy.
Copyright 2010 by the American College of Sports Medicine.