Light Exercise Helps to Prevent Osteoarthritis

The most common form of arthritis, osteoarthritis (OA) is a degenerative joint disease that causes pain, swelling and stiffness.  Thomas M. Link, from University of California/San Francisco (UCSF; California, USA), and colleagues studied 132 asymptomatic participants at-risk for knee osteoarthritis who were enrolled in the National Institutes of Health Osteoarthritis Initiative, as well as 33 age- and body mass index-matched controls. Study participants included 99 women and 66 men between the ages of 45 and 55. The participants were separated into three exercise and strength-training levels, based on their responses to a standardized physical activity questionnaire. Exercise levels included sedentary, light exercisers and moderate to strenuous exercisers, strength-training groups included none, minimal and frequent. Knee-bending activities were also analyzed.  MRI exams revealed that light exercisers had the healthiest knee cartilage among all exercise levels, and patients with minimal strength training had healthier cartilage than patients with either no strength training or frequent strength training. Moderate to strenuous exercise in women who did any amount of strength training was associated with higher water content and more degenerated collagen architecture in the knee. In addition, the findings showed that frequent knee-bending activities, such as climbing up at least 10 flights of stairs a day, lifting objects weighing more than 25 pounds, or squatting, kneeling or deep knee bending for at least 30 minutes per day, were associated with higher water content and cartilage abnormalities.  The researchers conclude that:  “Light exercise appears to protect against cartilage degeneration in subjects with OA risk factors, and moderate-strenuous exercise in females seems to be detrimental," urging that: "Modifying physical activity may be an effective intervention to prevent cartilage degeneration."