What’s the Pop in Chiropractic Adjustments? Here’s What It Really Means

The shudder. The squirm. The grimace.

I’ve seen all of them—usually right after I mention that a click or pop might happen during an adjustment. And yep, it’s completely normal. These reactions don’t happen every time, but when they do, I always ask curiously:

“What are you worried about?” or “What do you think that sound actually is?”

Most people look at me slightly puzzled—wondering why I seem so calm. And their answers? Here are some of my favourites:

“What if you break my neck?”

“It’s like a bone is breaking.”

“It sounds like it hurts.”

Every response is completely valid—especially when you think about it: someone you’ve just met is about to push, pull, or twist part of your body quickly. That can feel pretty daunting.

So in this blog, I want to explain what an adjustment actually is, and why you might hear that pop or click during treatment—because once you understand what’s happening, it often feels a lot less scary.

When chiropractors treat, we usually use a combination of techniques to help our patients reach their goals. These might include adjustments, soft tissue work, or exercises—similar to the kinds of care you might receive from a physiotherapist or osteopath.

(If you’re curious about how these professions differ, click here to learn more.)

That said, chiropractors typically favour the adjustment as a primary tool. You might hear us refer to it as a “High Velocity Low Amplitude” (HVLA) thrust. In plain English, this means we push, pull, or twist a joint very quickly, over a very short distance, and with minimal force.

We’re like The Flash—just in short bursts.

Because the movement happens so fast, many people expect it to hurt. But HVLA adjustments are not about brute force—they're about precision and speed, delivered after careful assessment.

So what does an adjustment actually do?

There are several proposed mechanisms—but one of my favourite ways to explain it goes back to something many of us remember from childhood.

If you scraped your knee, your mum or dad might have told you to “rub it better.” It sounds like an old wives’ tale—but there’s real science behind it.

Your body has different types of nerve fibres that carry different kinds of information. Some (called C-fibres) transmit dull, achy pain. Others (like A-beta fibres) carry information about touch, pressure, and movement.

Here’s the interesting part: your brain can only process so much input at once. So if a wave of non-painful input from A-beta fibres reaches the brain quickly, it can actually dampen the pain signals from C-fibres. This is known as the Gate Control Theory of Pain (Melzack & Wall, 1965).

When we adjust a joint, we stimulate these faster, non-painful pathways. That’s one reason people often feel relief and less tension straight after an adjustment.

Another proposed mechanism involves something called the Golgi tendon organs—tiny nerve receptors found where your muscles attach to tendons. These receptors monitor tension in your muscles.

When they detect a sudden or strong stretch (like during an adjustment), they send a signal to help relax the surrounding muscle. This can reduce protective muscle tension and temporarily allow for greater ease of movement.

That’s why many people feel immediate relief or increased flexibility after an adjustment—your body’s own reflexes have let go of some of the tightness that was holding you back.

As a result of these mechanisms, what most patients feel is a decrease in pain and an increase in how freely they can move—sometimes even within minutes.

In my treatments, I always assess joint movement first, identifying areas that aren’t moving well. Then I treat those restricted areas—often with an adjustment—and reassess afterwards. When the body responds with greater movement or less discomfort, it’s a sign that the nervous system is starting to adapt in the right direction.

Now let’s talk about the pop—or the crack—that many people associate with chiropractic adjustments.

That sound is called joint cavitation. It happens when the joint space opens slightly, causing a quick change in pressure. This shift allows tiny gas bubbles (mostly carbon dioxide) to rapidly release from the joint fluid—producing that distinct sound (Kawchuk et al., 2015).

An image of two bones being pulled away from each other. The gas bubbles form as they do so.

It’s similar to the sound you hear when cracking your knuckles. Within about 20 to 30 minutes, the gas re-dissolves—so you likely wouldn’t hear it again if the joint were adjusted immediately.

While the goal of an adjustment is to improve how a joint and the surrounding muscles function—not to create a sound—the pop can still feel satisfying. Research shows that the sound isn’t necessary for an adjustment to be effective (Moorman & Newell, 2022).

Still, many patients tell me:

“If I don’t hear the pop, I don’t feel like anything happened!”

And I get it—people want to feel like something changed. That’s why I use a test–treat–retest approach throughout the session. It helps confirm that your body is responding—and gives you real feedback beyond just the sound.

Final Thoughts: What is the pop in chiropractic adjustments?

Hearing a pop during an adjustment might feel strange at first—but now you know it’s not your bones cracking, and it’s certainly not something to fear. The sound is simply a byproduct of a well-timed, low-force movement designed to help your joints move more freely and your nervous system respond better.

Whether you’re nervous about the sound, curious about how it all works, or just want to feel more in control of your care, I hope this blog helped make things clearer.

📍Still have questions? That’s completely normal. If you're curious about whether chiropractic care might be right for you, I’d be happy to chat. Next week, I will walk you through what a typical first visit looks like, from the moment you walk in the door to when you walk out again.

🗓️ Click here to book a consultation or find out what your first visit would look like.

References:

Melzack, R., & Wall, P. D. (1965). Pain mechanisms: a new theory. Science (New York, N.Y.), 150(3699), 971–979. https://doi.org/10.1126/science.150.3699.971

Kawchuk, G. N., Fryer, J., Jaremko, J. L., Zeng, H., Rowe, L., & Thompson, R. (2015). Real-time visualization of joint cavitation. PloS one, 10(4), e0119470. https://doi.org/10.1371/journal.pone.0119470

Moorman, A. C., & Newell, D. (2022). Impact of audible pops associated with spinal manipulation on perceived pain: a systematic review. Chiropractic & manual therapies, 30(1), 42. https://doi.org/10.1186/s12998-022-00454-0