251- The Neurophysiological Effects of an Adjustment
11 Nov 2025 · 0 min
Podcast episode (Evidence Based Chiropractor, host Dr. Jeff Langmaid) focused on the neurophysiological mechanisms and clinical implications of spinal manipulation/adjustment, based principally on a 2002 Spine Journal review. The episode explains how spinal manipulation produces mechanoreceptive input to paraspinal primary afferents (group 1A/2), influences central sensory processing and pain thresholds via central facilitation, affects the neuroendocrine system, and alters skeletal muscle reflex control. The host emphasizes a movement-continuum model (segmental → regional → whole-body), the multi-factorial nature of manipulation (biomechanical, peripheral, central effects), and practice implications for patient education, rehab progression, and marketing.
Welcome to the Evidence Based Chiropractor, where each week we deliver the latest chiropractic research and marketing strategies, all in the time it takes to get to your office. Now, here's your host, Dr. Jeff Langmaid.
Hello and welcome to the Evidence Based Chiropractor. I am your host, Dr. Jeff Langmaid. And on today's episode we are talking about the chiropractic adjustment or spinal manipulation, depending upon your choosing. We're talking neurophysiological effects of spinal manipulation. This paper came out in the Spine Journal a few years back. I love it because it breaks down how an adjustment works to the best of the knowledge at the time the paper was published. We continue to learn more, but I know that there's a lot you can take away from this study, apply to your clinical decision making, and also have a better understanding of how what you do every single day works. We're gonna break this paper down on today's episode. Before we get started, I'm recording this episode a couple days early. So next week I'll announce the winner of the contest we held on episode 250, which was to leave some feedback on itunes regarding the podcast. And I'll select somebody at random and you will win a poster set from the Evidence Based Chiropractor. Also, one other announcement. If you want to step up your marketing game, we have open enrollment going on right now at The Smart Chiropractor, thesmartchirofractor.com Email in office TV, streaming, social media, and much more. All done for you. Monthly campaigns, weekly topics, Daily Post. We just took a poll with all of our members in our group and the average Smart Chiropractor member is generating 10 or more, 10 or more patient activations each and every month consistently. And this is not leads. These are people on your schedule. That's what the Smart Chiropractor is all about. Automating your content marketing. Open enrollment is going on right now, so be sure to check it out atthe smart chiropractor.com but as I said at the top, we are talking all about neurophysiological effects of spinal manipulation and this came out in spine journal in 2002. So we know spinal manipulation, hallmark of chiropractic care, has been used for over 100 years to treat various physical ailments. But the question of how it works has always been a little bit elusive to answer. And it's recently been discovered that the biomechanical changes that occur during manipulation have physiological effects on the inflow of sensory information to the central nervous system. And this is sort of what we've seen. We'll talk about how what I guess group of nerve fibers this runs through, but really we've seen this time and time again. You input the sensory information, the mechanoreceptive input from the adjustment, the thrust itself. Right. And that stimulates or activates the central nervous system. The mechanical input can reduce nociceptive input pain gating. It can reset neural integration. When that starts to get really interesting, because we see sensitization with many of the neural pathways due to pain or due to trauma or due to nociceptive input. So when you can reset that neural integration, reset those thresholds, that's really, really powerful because it's a natural way to again reduce pain and improve function. It can also stimulate muscle spind in a way that improves physiological function. So we see that stretch response on those muscle spindle fibers, which often leads to a relaxation type effect. Now, the multi factor mechanism of action also clarifies how to some degree why spinal manipulation has been shown to provide relief for a wide array of neuromusculoskeletal issues. And I think this has been some of when we break down an adjustment or what we do as chiropractors to a single thing, mechanical, low back pain, you know, neck pain only, migraine headache or something like that, it can be studied pretty intently in that realm. But one of the catch 22s about what we do has been such a wide array of what we're able to effectively take care of, treat and or mitigate, depending upon how you want to put it right. We have our neuromusculoskeletal issues. I don't think there's a chiropractor out there that would say, hey, we're not really experts in really the best, one of the best, at least conservative care options. I mean, take conservative care out of it. We're one of the best care options, bar none, for a wide array of neuromusculoskeletal issues. Then you add on some of the organic things that we see, what else anecdotal evidence with, and it just starts to get so wide, you're like, how the heck is this working an adjustment and how does it affect so many different things? Some of that takes place, I think because of what we've seen here, that it's a multi factor mechanism of action. There are brain changes we've seen in previous studies. There is central nervous system facilitation, there is peripheral nervous system input. There's literally the joint mechanics when you get in there and break up an adhesion. There is so much to what we do that it starts to become a spider web. When research really strives to create a spider fiber or spindle and we have a spider web, it's hard to search out those answers. But we're starting to learn more and more and get there each and every year. So let's take a look at a couple quotes from this study. We'll continue to break it down a little bit more into really tangible pieces for you. Researchers found, quote, strong evidence supports using spinal manipulation to help patients with acute low back pain and neck pain. That we know, but it's always nice to see it in print. So strong evidence. This is not something that is conjecture. It's not something based on placebo. This is strong evidence about using spinal manipulation or an adjustment for acute low back and neck pain. The researchers also cited, quote, numerous studies suggest that spinal manipulation alters central processing of innocuous mechanical stimuli because pain tolerance or threshold levels increase. Again, this gets back to that balance between nociceptive input, between mechanoreceptive input, and the fact that when we get in there and really light up those mechanoreceptors with an adjustment, there really is a central nervous system process that takes place that's done different than if you don't do it. And that tends to reset these threshold levels for pain tolerance, which is very, very important because in chronic pain, which 30% of the world, what they're estimating, 30% of the world, is living with chronic musculoskeletal issues. Resetting those thresholds is an exceptionally important part of it. Chronic pain, by definition, is pain that has gone from an acute phase short term, and your body has adapted to it and sensitized to it. And that's where we see non nociceptive input causing pain. Because the threshold levels of what is tripping the quote, unquote feeling of pain in the brain is just altered so dramatically because of. And due to that initial acute injury, our body's sensitized to it and you start to just kind of get that snowball effect. So changing those threshold levels, not altering them with dangerous medications or, I mean, we don't even need to talk about opioids in this episode. But there are ways to do this that don't require medicine. They don't require these sort of risky and dangerous type things. And it's what you do as a chiropractor. So getting out there and telling that story is very, very important. Research has also found, quote, spinal Manipulation evokes changes in the neuromusculoskeletal system. The experimental evidence indicates that the impulse load of a spinal manipulation impacts proprioceptive primary afferent neurons for paraspinal tissues. In addition, spinal manipulation can affect pain processing, possibly by altering the central facilitated state of the spinal cord, and can affect the motor control system. So a lot to dissect in that statement, but basically what it's saying is what we've talked about the first few minutes this episode. There is a lot of stuff going on. So when you deliver an adjustment, there's an impulse to the proprioceptive afferent neurons in the paraspinal tissues, right? That's what's happening right there, where you're delivering that adjustment, that input into proprioceptive. And after that, that's where the cascade starts. So that's when that proprioceptive input in the periphery, the paraspinal tissues, goes into the spinal cord, gets transmitted up to the brain and we start to see that reflex go back down or ultimately the information flow go up and down. So what is the current evidence for the neurophysiological mechanisms of spinal manipulation? Here are the top four things that I took away from this study. This is a little geeked out on spinal anatomy, but it'll be a good refresher if you haven't thought of this lately. IT alters group 1A and group 2 mechanoreceptor discharge. It influences sensory processing in the spinal cord via central facilitation. It affects the neuroendocrine system, and it impacts control of skeletal muscle reflexes via somatosensory reflexes. All of these things really, really interesting and really important. And it's how you get the results that you do day in and day out in your practice. And the adjustment, the spinal manipulation is a powerful, powerful thing. The neural inputs could influence pain producing mechanisms as well as other physiological, controlled or influences by the nervous system. And that's powerful. Releasing trapped meniscus, discal material, segmental adhesions. All of this is part of what we do with an adjustment and movement. It all comes down to movement. When I think of movement, I think about it in terms of three stages or brackets. I think of whole body movement, typically what we call exercise, right? So there's exercise and whole body movement exceptionally important. We know that from a variety decades and decades of studies. We also then look at regional motion, regional movement that could be of a body region, neck, low back thoracolumbar, cervical thoracic area. But then we also look and that's exceptionally important as well. Then we look at the third, which is segmental motion. And that's where we have the absolute direct corollary with the spinal manipulation or with an adjustment, is improving and enhancing and influencing the segmental motion. And you really need the continuum of all three, right? You can have great segmental motion, but if you're not exercising or going through any stretches and doing regional things well, are you getting the most? Are you as healthy as possible? The answer to that's probably no. On the other end of the spectrum, if you exercise all the time, you have great whole body movement, but you have segmental dysfunction like crazy. You have fisch joints that are locked up now. You're talking about massive compensations that can lead to injury down the road, potentially. It could lead to potentially advanced degenerative change. I mean, there's a lot that can happen. You really need the continuum. And I think for a lot of us as chiropractors, this might be something I further explore on future episodes. I don't think we talk about that continuum or those three brackets of motion. I need to come up with better words for that. But the three brackets of motion, whole body exercise, you know, regional, which could be your stretching and exercise, obviously it's a continuum, so it gets in there. And then segmental, which really lives with the adjustment, but obviously stretching gets in there as well. I think that's a really important talking point for us, because when somebody has great whole body movement, regional movement, and segmental motion, they're probably doing pretty good, right? You know, from a health perspective, from a neuromusculoskeletal perspective. And I think we need to talk about that more and have people understand to a certain degree, some of the progression that we do when we go from active care to passive care in our practices is about, well, let's get down to it, right? Let's find the cause. And many times that's a segmental issue. Not every time, but many times it's a segmental issue. And then you progress people into rehab exercises at home care that goes more towards the regional and the whole body, right? So when we look at the lens of movement as chiropractors, a lot of times we look at it through the lens of segmental motion. Now, I mean that in terms of how we're delivering our care, you might be FMT certified, you might, you know, be a Greg Koch follower. Maybe you're going through and you are doing all of your movement assessments that take into account all of the whole Body and regional movement at the beginning. And that's great. If you're doing that, keep doing that. But you're probably always looking at it from a treatment lens in terms of, okay, how do I get motion into this joint? Now let's go back and go out into regional and whole body. And again, this is not absolute. It's a continuum. You can play with it, but having these types of conversations and understanding where you want to progress somebody throughout their care is an important piece of being a great chiropractor. There are so many docs out there, and I know there's so many evidence informed docs out there that have great gym spaces that ever get used, they pride themselves on. We get people out of pain in two visits and get them out the front door. That's great if that's the way you want to go about it. But my thing is, if you have a great rehab space and you know that pain is the last thing to come, the first thing to go, and that the person's biomechanics and movement patterns are horrific, and we all know patients are noncompliant doing things at home 99% of the time. Take the opportunity to guide them there. Take the opportunity to keep them within your ecosystem. Take the opportunity to showcase the knowledge that you have to and make it compelling for the patient so that they understand if they think they're only there for pain relief. If they only want to be there for pain relief, doesn't mean about forcing them to do anything that they don't want to do, but it means offering them the opportunity to do more if they choose to. And I think a lot of evidence informs docs, even those that have these great gym spaces, these great rehab spaces, those spaces are rarely used or they're rarely used to capacity and they have people flowing out their front door all day long and they just don't give the opportunity for the patient to really dive into the knowledge that you have. And when you can explain it in the fashion of, hey, you know, we're going to work on everything, but here's our progression. Number one, we're going to get you out of pain by doing X, Y and Z. Number two, we're going to work on your biomechanics to ensure that you have good movement patterns moving forward. And number three, we're going to really focus on performance. If you can explain that in a way, and it aligns, of course, with what the patient desires, now you have a really compelling value proposition and you're doing your best patient centric work. So hopefully these neurophysiological effects of spinal manipulation. This paper, I think, is a good one. It does get super technical. We sort of skim the surface on a lot of it because a lot of it gets down to spinal anatomy that is super complex. But some big takeaways there are. Think about movement, think about how the adjustment is impacting your patients, explain it in the most patient friendly, patient centric way that you can, and ensure that you are giving your patients every opportunity they have to continue to learn from you, continue to train with you. Because I'm gonna tell you, as a chiropractor, you have a special skillset and you should ensure that people have the opportunity to work with you if they choose to do so. So have a fantastic week in practice and I will talk to you soon.
Thank you for joining us on this episode of the Evidence Based Chiropractic. If you want to grow your practice, come back for next week's episode. If you want to grow faster, visit the evidencebasedchiropractor.com and join our MD Marketing membership today.
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