Myth: Cracking your knuckles (or other joints) will give you arthritis.

Fact: Cracking your joints does no damage and, in fact, protects them against arthritis. Researchers at Johns Hopkins University found that osteoarthritis is more often present in those who never crack their joints (fingers, backs knees) than those who do.  That may be because cracking a joint reduces the space within it and results, at least temporarily, in a greater range of motion and flexibility.