1. Watch your weight. Extra weight can strain the joints, especially the knees and hips. Over time, this strain can lead to arthritis. The good news is that even a small reduction in your waistline can lead to a big reduction in your risk. A 1992 study published in the Annals of Internal Medicine found that women who lost an average of 11 pounds over 10 years cut their risk of osteoarthritis in the knee by half.
  2. Avoid injuries. Don't wait until your golden years to start protecting your joints. No matter what your age, serious injuries to joints -- torn ligaments, torn cartilage, or broken bones -- can lead to arthritis somewhere down the road. A study published in the September 5, 2000, issue of the Annals of Internal Medicine found that people who injured their knees as teenagers and young adults were nearly three times more likely than those without injuries to have osteoarthritis by the time they reached 65.
  3. People who participate in intense sports like football, basketball, soccer, and gymnastics are especially vulnerable to joint injuries. But just about any type of exercise can be dangerous if you push yourself too hard. The American Orthopaedic Society for Sports Medicine urges people to follow the 10 percent rule: If you want to boost your activity level (a noble goal), do it just 10 percent at a time. For example, if you normally jog one mile a day, try jogging 1.1 miles the next day, not four.