Whether it is to alleviate boredom, stress or tension, stiffness, restlessness or simply due to habit, knuckle cracking seems to satisfy many. A study in the Journal of the American Board of Family Medicine reported that the behavior is often habitual because of the release of joint tension and increased range of motion knuckle cracking can cause.
There has been much debate on what knuckle cracking actually is. Previously, the theory was that the cracking sound came from the collapse of bubbles in the synovial fluid when the joint is separated. Recently, scientists from the University of Alberta used real-time magnetic resonance imaging (an MRI) to see just what happens when a joint “cracks.” They successfully debunked the long-standing bubble theory, as they found visual evidence of cavity formation — a rapid formation of gas within the fluid surrounding the joint. Think of the sound you hear from the gas escaping a soda can when you pop the top. While the physics are not exactly the same, it helps to envision how the gas in your joints can make a sound when you manipulate them to the point that they “crack.”
If you have cracked your knuckles in public enough times, you have surely been granted the unsolicited advice that you will get arthritis. Studies show that habitual knuckle cracking does not cause osteoarthritis, the most common form of arthritis. The affliction can be caused by joint injury or overuse, but not directly from cracking of the joint. Pushing the joint beyond its ability in order to get it to crack can certainly cause injury, which can eventually lead to osteoarthritis, but the cracking itself would not be the cause. Overextending the joint can also damage the surrounding ligament or dislocate the tendon. There has been speculation that knuckle cracking can weaken your grip, however, a 2017 study in the journal Hand Surgery & Rehabilitation found that knuckle cracking does not affect your grip strength. So, the next time someone hits you with the arthritis line, you can feel free to pull, stretch, or bend your fingers as you wish.
So, if cracking your knuckles does not cause arthritis, what about cracking the rest of your body? Jennifer Bevis, D.C., of Bevis Chiropractic in Gainesville said cracking your back or neck is best left to professionals. Stiffness in your back or neck can be caused by vertebrae that are misaligned (called a subluxation), and when you crack the area, you are not actually stretching the problem area. “Other vertebrae above and below start to move a little more to allow you to bend, so they are working double time and doing more motion than they should. Now you are creating a more hypermobile situation, and hypermobility leads to degenerative change,” said Bevis. “A professional can evaluate where the problem actually is and do an adjustment focused on that area.” Basically, you are not alleviating the stiffness in the problem area, but further stretching areas that are already compensating for the stiffness. Bevis explained that stiffness and hypermobility also relate to knuckle joints and recommends not using knuckle cracking as a method of self-medicating.