I was seven years old when I first saw someone with severe rheumatoid arthritis. I had just met one of my grandmother's cousins, whose swollen joints and gnarled fingers fascinated and terrified me. I asked my mother why her hands were like that.
“She has arthritis. That’s why you shouldn’t crack your knuckles,” my mother said, injecting about a year’s worth of terror into my overactive imagination. I vowed not to crack my knuckles, so as to not incur a premature onset of the inflammatory condition—all because of my mom’s throwaway comment.
I held out for a few months before stealing some quick cracks here and there, only to meticulously study my knuckles for hours to see if they had swollen up. (For the record, cracking your knuckles does not cause arthritis.) It wasn’t long before I reverted to my old habit—and more than fifteen years later, I am still cracking.
While the premise of those crack-free months was founded in a lie (thanks, Mom!), it raises an interesting question: Is it beneficial, or even possible, to fully quit cracking your knuckles?
While everyone has an opinion on cracking knuckles—some non-crackers equate the sound to nails on a chalkboard—much is still unknown about the physiology.
“There are lots of different ideas, and we don’t know for sure yet," Greg Kawchuk, a professor of rehabilitative medicine at the University of Alberta, told Fusion. On a basic level, we do know that cracking affects the pressure that can build up inside a joint, creating a little distance between the joint's surfaces—and relieving a feeling of tension.
Until recently, however, scientists wrongly believed that the "cracking" sound occurred when joint fluid bubbles burst, but Kawchuk and a team of researchers revealed earlier this year that it actually comes from the formation of bubbles. As part of the research, Kawchuk captured the physiology of knuckle cracking on an MRI for the first time, as shown here:
Kawchuk explained that cracking your knuckles is kind of like stretching any other part of your body. And yet, not everyone has the ability to crack his or her knuckles—something researchers are curious to explore further.
So scientists are still trying to get to the bottom of knuckle cracking. But given what we know, is it even possible to break the habit? Or, once we start, are we biologically bound to keep cracking forever?
We spoke with Judith Beck, clinical associate professor of psychology in psychiatry at University of Pennsylvania and president of the Beck Institute of Cognitive Behavioral Therapy, whose short answer was, yes, it is possible.
Beck said that her therapy regimen for breaking a knuckle-cracking habit might include some combination of putting bandaids on knuckles as a reminder; replacing the habit with something else (like snapping fingers); writing down a list of reasons why one feels compelled to crack; and helping one understand the psychology behind craving and impulsive behaviors.
Beck also suggests rewarding yourself every time you successfully resist the urge to crack. This builds up a sense of "self efficacy," she said—reinforcing the idea that you can quit.
From a physiological perspective, some people think that the more you crack your knuckles, the looser the joints become, and the easier they are to crack. But Kawchuk calls bull. "There is no research to support that idea, which seems to be more of an old wives' tale," he said.
While Kawchuk said there are, in fact, people who feel they need to crack their knuckles to function, Beck believes this feeling is rooted more in a mental fixation.
“Sometimes they have an all-or-nothing idea about it—either I crack my knuckles and I can move my joints flexibly, or I don’t and I can’t. And that’s unlikely to be accurate,” she said, acknowledging the lack of physiological understanding of cracking joints in general.
"When people have ideas about stuff like that, they have an image in their head about what’s happening inside their joints—which is, again, probably inaccurate," Beck explained. "It’s a thought: 'I can’t move it quite as well.' It’s a sensation of not being able to move. But there’s also a picture in their heads of when it feels right."
In other words, people are more likely to adapt their behavior to suit what they imagine is going on, according to Beck—a tendency that isn't helped by the fact that even experts can’t give us a precise picture of what’s happening beneath the surface.
So it is possible to stop cracking your knuckles. Now, whether or not there’s a physiological benefit to the habit? Well, we just don’t know yet. Better crack them just in case, right?