What Is the Cracking Sound at the Chiropractor? Is it Good or Bad?
Thanks to social media, most people have now seen videos of chiropractors administering treatment to patients. Scroll through TikTok or Instagram for long enough, and you're bound to come across one. What strikes me about a lot of these videos is that they tend to focus heavily on — or even sensationalise — the "crack," "click," or "pop" sounds you often hear during spinal manipulative therapy (SMT). Rarely, though, do they actually explain what those sounds are, or what they mean.
In my experience as a chiropractor, people generally fall into one of two camps when it comes to the click:
a) They love it ❤️— and will often specifically request it, or feel short-changed if it doesn't happen.
b) They hate it 🤬— and will tense up in anticipation, or actively avoid treatment because of it.
Interestingly, some people click a lot, while others barely at all — and looks can be surprisingly deceptive in that regard. So what's actually going on?
What Is SMT?
Spinal manipulative therapy (SMT) is a hands-on technique used by chiropractors to restore movement and function to joints of the spine and body. It involves applying a controlled, precise force to a specific joint — typically one that has become restricted or isn't moving as it should. The goal is to improve mobility, reduce pain, and help the body function more effectively.
It is one of the most well-researched manual therapy techniques available, and is a core part of what we do here at HEALTH SHAK.
So What Is the "Click"?
The sound you hear during SMT is called a cavitation. Here's what's happening: your joints are surrounded by a fluid called synovial fluid, which acts as a lubricant and contains dissolved gases — approximately 80% of which is carbon dioxide. When a joint is manipulated, the pressure inside the joint capsule changes rapidly. Current research suggests this causes a gas cavity to rapidly form within the synovial fluid, and it's that sudden formation which produces the characteristic pop [1].
Think of it a little like the moment you pull a suction cup off a window — two surfaces resist separation until a critical point, and then suddenly release.
Now, here's the important bit: the research suggests that the sound itself has no clinical significance. The cavitation does not tell us:
Whether a joint has moved more or less than intended
Whether it moved in the right direction or the wrong one
Or even whether it moved at all [2, 3]
The click is, in essence, a byproduct of the technique — not a measure of its success.
So, Should I Read Into It?
In short: no.
Throughout our lifetimes, most of us have built up associations and assigned meaning to that sound. You might have been told as a child not to crack your knuckles, or else you'd get arthritis (you won't, by the way — research has firmly put that myth to bed [4]). Or perhaps you've seen videos online of someone being dramatically "fixed" after a loud click, and drawn your own conclusions.
These associations are understandable — but they can be misleading.
The click is neither a sign that something good has happened, nor that something bad has. It is simply an incidental finding — something that sometimes occurs with SMT, and sometimes doesn't. A treatment isn't more effective because it was louder, and it isn't less effective because it was quieter.
Final Thoughts
If you often feel like you need something "clicked," what you're most likely experiencing is a joint that needs to move — and that's exactly what we're here to help with.
At HEALTH SHAK, we are specialists in spinal health and posture correction. Whether you're a click enthusiast or someone who'd rather never hear the sound again, we'll always tailor your treatment to what's right for you — not what sounds most dramatic.
Ready to get moving?
📞 020 7856 0573
📍 11 Heathfield Terrace, Chiswick, London, W4 4JE
References
Kawchuk GN, Fryer J, Jaremko JL, Zeng H, Rowe L, Thompson R. Real-time visualisation of joint cavitation. PLoS One. 2015;10(4):e0119470. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4398549/
Dunning J, Mourad F, Barbero M, Leoni D, Cescon C, Butts R. Bilateral and multiple cavitation sounds during upper cervical thrust manipulation. BMC Musculoskelet Disord. 2013;14:24. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565891/
Dunning J, Rushton A, Butts R, Mourad F, Fernández-de-las-Peñas C, Hagins M, et al. Cavitation sounds during cervicothoracic spinal manipulation. Int J Sports Phys Ther. 2017;12(4):642–54. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5534155/
DeWeber K, Olszewski M, Ortolano R. Knuckle cracking and hand osteoarthritis. J Am Board Fam Med. 2011;24(2):169–74. Available from: https://www.jabfm.org/content/24/2/169
