The ability to maintain balance is critical to preventing falls. Given that the knees are the body's primary weight-bearing joints, factors such as knee strength or knee pain likely affect how steady we are on our feet. A group of researchers examined the interplay between strength, obesity, and knee pain on balance in a group of older Americans. Their results appeared in a recent edition of the Journal of the American Geriatrics Society .

The researchers used information obtained from 480 men and women enrolled in a 30-month study designed to examine factors affecting the severity and progression of physical disability from knee pain. All of the participants reported experiencing knee pain on most days that was severe enough to cause difficulties with one or more activities such as walking a quarter mile, climbing stairs, rising from a chair, cleaning, or lifting and carrying groceries. The average Body Mass Index (BMI) -- a measure of body fatness -- was 29. (A score greater than 25 indicates that a person is overweight.)

The investigators measured participants' balance during movement, as well as their knee and ankle strength. X-rays were taken to determine whether there was any evidence of osteoarthritis in the knee and if so, to what degree.

Stronger legs, better balance

X-rays showed that more than half of the participants had a moderate degree of osteoarthritis in the knee. Those with the strongest knee and ankle muscles, however, were better able than those with poor muscle tone to stay flexible and balanced in spite of persistent knee pain. Body weight was also a factor--those at a healthy weight scored better on balance tests than did overweight individuals.

The virtues of exercise

As this study indicates, strength can be an important factor in keeping aging joints healthy. Joints surrounded by toned muscles are bettersupported and hence less painful. Some doctors think that strong quadriceps muscles (the muscles in the thighs that support the knees) may reduce the likelihood of developing knee osteoarthritis, a condition evident in the majority of this study group. Strong quadriceps can also slow the progression of knee osteoarthritis in people who already have the condition.

Although the study does not address this issue specifically, exercise is essential to maintaining knee strength. Those who already suffer from osteoarthritis may feel limited by their condition, but there are several exercise options open to people with knee pain. Swimming and water aerobics, for example, can assist in both overall fitness and muscle strength without placing undue stress on joints.

Walking, in good shoes and on level ground, can also improve the function of arthritic knees. Additionally, regular exercise helps keep weight at a healthy level, reducing the stress on sore knees. A doctor or physical therapist can provide guidance on appropriate activities. The Arthritis Foundation (see link below) also has practical advice on how to start and stay with a safe exercise program.

Source

Strength, balance, and the modifying effects of obesity and knee pain: results from the Observational Arthritis Study in Seniors (OASIS).
K. Jadelis, ME. Miller, WH. Ettinger,  et al., J Amer Ger Soc., 2001, vol. 49, pp. 884--891

Links

• Weight Loss and Exercise Can Help Sore Knees
• A new Injection Treatment for Osteoarthritic Knees?
• Excess Weight Adds Health Problems, Too
• Find out your BMI
• The Arthritis Foundation
• To quickly access additional accurate information on this and other nutrition-related topics, visit Tufts University's Nutrition Navigator