Is it bad to crack your knuckles?

Probably: Your grandmother would likely condemn the process, which makes it unwise, no matter what reality says. However, it can advance arthritis, loosen ligaments, enlarge the joints, and cause worsening pain in the joints (usually prompting more cracking).

No: Contrary to the other answer to your question, studies have shown that cracking knuckles does not cause arthritis or make preexisting arthritis more severe.