492- Exploring Neuromuscular Responses to Spinal Adjustments

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. On today's episode we have a super exciting study that we're gonna dive into a brand new one all around the neuromuscular response to spinal adjustments. This is an awesome study. Can't wait to dive in. But before we do, if you have not checked out the new and updated Patient Pilot, head over to thesmartchiropractor.com if you have a patient list that you are not communicating with consistently, please please please head over to the smart chiropractor.com and check out what we have going on at Patient Pilot Automated Patient Reactivation emails going out to your patient list each week where you get to choose the topics, the campaigns that go out. You get to put in a welcome back offer. Doesn't need to be deep discount but provides clarity. Super unique in this space. We're the only ones doing it and docs that have a good list and docs whose patients want to come back and see them. This is just a ton of total layup. Make it easy for your people to come back in and see you instead of exclusively focus on trying to get the new ones. Put a patch those holes in the bottom of your bucket. I guess as I should say, you can learn more over atthe smart chiropractor.com or hit me up directly if you have any questions, but on today's episode we're talking research. As always, I will drop a link down in the show. Notes we're going to dive deep into a comprehensive overview of of neuromuscular responses to spinal adjustments. This was published in January 2025 and it is titled appropriately Neuromuscular Response to High Velocity Low Amplitude Spinal Manipulations. An Overview this review pulls together findings from over 135 studies on neuromuscular effects of high velocity low amplitude spinal manipulation, which I'll just call spinal adjustments. Moving forward on today's episode, including muscle activation, reflex changes, muscle strength, cortical responses. So if you've ever wondered and wanted to know, and if you listen to this podcast, hear me talk about it a little bit. But how a spinal adjustment affects the body beyond just pain relief, this episode is gonna give you the data and the insights to back up what you do each and every day in Practice. So we know spinal adjustments are one of the oldest and most widely used manual therapies out there yet. Yet the neuromuscular mechanisms are still not fully understood and it's gonna take a serious amount of time before they are. Why? Because the breadth and depth of what happens when you deliver an adjustment is so great that it takes time and we learn a little bit here, a little bit there. But this contributes to the decades of research to clarify how spinal adjustments affect things like muscle spindle activity, electromyography, EMG motor evoked potentials, reflex responses, cortical processing. And there's a great quote from the study where they say, despite an increasing amount of spinal adjustment research, our mechanistic knowledge related to its neuromuscular effects remains limited, primarily due to small sample sizes, inconsistent methodology, and a lack of standardized adjustment data delivery. Now, some of those things aren't going to be solved overnight, but some of them can be. And this study is another brick laid in the road of understanding, which is what I really, really love. So let's start out with muscle activation in EMG responses. Electromyography EMG measures muscle activation after an adjustment. And the findings were a little bit mixed, but really promising. Short duration thrusts, 100, 150 milliseconds produce the most significant EMG responses. Particularly in no surprise, the paraspinal muscles and limb muscles. Trunk EMG responses typically occur within 0 to 40 milliseconds after a thrust and last up to 40 milliseconds. And the clinical takeaway here was your body, a body, the body, your patients. Bodies respond rapidly when you deliver a chiropractic adjustment, and not just locally, but across multiple muscle groups, indicating that there are central and peripheral nervous system activations going on. That is important. Notably, they found bilateral increases in biceps EMG activity after a cervical adjustment, suggesting that the neurological effects that they extend beyond the site of adjustment, which is important, I think we all know, but important to continue to see documented, important to continue to understand. Of course we want specificity with our diagnosis, we want specificity with our care and treatment, specificity with our everything that we do. But it's also important to recognize the fact that when you deliver an adjustment, yes, it takes effect at that specific location, but there are far reaching implications as well throughout the central and the peripheral nervous system. Now, when we look at reflex responses, things like H reflexes, V waves and M waves, this study provides extensive data on reflex response modulation following an adjustment. H reflex amplitude often decreases after an adjustment. That suggests reduced motor neuron excitability. V wave amplitude increases, indicating enhanced cortical drive to motor neurons. Love hearing that. M wave responses largely unchanged, suggesting that spinal level excitability is more affected than the peripheral nerves themselves. So what's the key insight there? The fact that H reflexes are reduced while the V wave is increased. The may indicate a rebalancing of excitatory and inhibitory signals within the spinal cord. That's awesome. If I could draw it up, that's what I'd love to. That's what I would love to be the answer. So it's really awesome when we see that again you deliver that adjustment. There's a reduced excitability in the motor neuron. That's great. We also see that there is an enhanced cortical drive in the motor neurons. A decreased excitability, but. But an increase in drive. That's great. That is a rebalancing a regulation that is important and impactful. Then we look, when we start to look at how that really impacts the person and their life. Right. So let's take a look at muscle strength and cortical drive as well. Spinal adjustments. In the past, we've highlighted a couple of these studies on this podcast. They've been shown to temporarily increase muscle strength in various muscle groups. That doesn't mean that you get adjusted one time and you become a world champion championship bodybuilder. What it does mean is that there's temporary increases in muscle strength. That's meaningful and important. And I feel like it's been overlooked and I don't think it's been appreciated because it's. Well, it's just temporary and that is massive. So let's dive into some details. Biceps brachii and the deltoid strength increased after cervical and thoracic manipulation or adjustments. Leg strength increases in military personnel after four weeks of regular spinal adjustments. Hand grip strength increased in judo athletes and in those with lateral epicondylagia after cervical adjustments. So the quote from this study, short term increases in muscle strength after an adjustment are likely due to changes in cortical drive. But the duration and clinical relevance of these effects remain unclear. Super fair statement. However, man, talk about exciting that you can with your hands deliver an adjustment and it can actually impact somebody's muscle strength and abilities. That is massively impactful. I think there's just so much opportunity in the sports performance realm with that that is untapped and yet to be talked about. I can't wait to talk about the future studies on this show as we start to see the impact of that over time, I don't think I've seen a study take place where there have been athletes measured pre and post over a significant amount of time that have received regular chiropractic care. Now there's a lot of factors that go into that that can alter variables, right? Their diet, are they injured? What is their diet, are they in season, out of season, how much are they working out? Right. Besides the adjustments, there's a lot of variables with that. That's going to be really tough to nail down specifics. But, but man, is that exciting. When we see what we do can regulate neuronal activity, that can increase strength, that can change reflex response. And now let's talk about EEG and cortical responses. And this is one of the most intriguing findings is the cortical changes measured by EEG somatosensory evoked potentials. SCPs showed significant attenuation of the N30 waveform. What does that mean? It indicated altered sensory motor processing. EEG activity increased in the frontal and parietal regions of the brain, suggesting heightened sensory integration and motor planning after an adjustment. Now resting state. EEG studies showed increases in alpha activity, particularly in the default mode network, an area associated with pain perception and self awareness. What's the takeaway here? This is a massive one. Spinal adjustments don't just impact muscles. It literally modulates. We've talked about this the last few episodes as well. It literally modulates brain function and sensory processing, offering a true neurophysiological explanation for effects on pain and function. Now what are some of the clinical implications? We could probably do hours and hours of this, but I will keep it as brief as humanly possible, which is there's tons of research and this research, this recent research, continues to show that spinal adjustments not only relieve pain, but can enhance muscle activation and reflex responses, indicating that what you do as a chiropractor influences the nervous system to work more effectively. What is a more powerful message? Now that might be not exactly how you'd say it on a social channel or exactly how you'd say it on a flyer, but the core essence of that is a message that is massively powerful to anybody who cares about human performance in your community. This goes beyond pain. Last week we talked about pain. Now we're talking performance. A spinal adjustment can recalibrate, literally recalibrate how your brain processes pain signals and improve muscle strength and coordination even after a single session. Now, we're not going to make guarantees, we're not going to extrapolate the research to try to Be something it's not. But that is a true statement based upon what we have seen to date. So how do you leverage this one? Highlighting that what you do with an adjustment is not just passive, it actively engages the nervous system and restores optimal function that's massive. Incorporating muscle strength testing, biofeedback, demonstrating changes pre and post. These are all things that if you choose to, you can dive into. And again, educating your referral partners, emphasizing the neurophysiological mechanisms of an adjustment and ensuring that they're up to date with this research. I can guarantee you nobody in your community knows about this research. Why? Because number one, it just came out and number two, they're really busy and they're probably not tracking chiropractic research day in and day out like I am and like you are by listening to this podcast. So sharing this is a fantastic way. We will share this through the MD Connection for all of our members, will highlight it in a personalized fashion with their monthly research briefs so that they can get out there and build a relationship. So if you are not on board with MD Connection yet you're listening to this podcast, I can't stress it enough. For less than 100 bucks you get access to the entire program that lays out everything a through zone. Highlighting how you can build relationships with other healthcare providers in your community. If you're serious about taking care of people, if you're serious, when you are there for the health of your community, you have to be reaching out to other people, other healthcare providers. If not, you're just not taking it seriously enough. Why? Because a good chunk of people will never come in to see you unless they are referred. It's just the way it is right now. So continue to do all of your new patient acquisition through your website, social media, getting those referrals from your existing patients. But don't sleep on the fact that that's the smallest pool. The largest pool out there are the fact that 99% of people are seeing other doctors in your community and only a fractional percentage will ever go see a chiropractor on their own. So get out there and build those relationships. It's just good business. And it's just being a good chiropractor, it's being a good community member. It might take a little time, might take a little effort, but man is it worth it. And this study shows that rapid short term changes in muscle activation, reflex and cortical activity support the neuromodulation that happens after somebody gets an adjustment. And that this is super complex. There's layers of sensory receptors, cortical processing, motor neuron input. There's a lot going on and what this means is that it's not just mechanical, it's neurological. And that this is not just bone doctoring. We, we you. You're influencing the nervous system at every level, from muscles and reflexes all the way to cortical processing. I love this study. Of course I'll drop a link down in the show notes so you can check it out. And before we wrap up, of course I want to say a couple words about Turncloud. Schedule a time if you haven't with their team and have a conversation. Super, super great software where you do not need a user manual. Have you heard that with an EHR before? Head over to turncloud.com, schedule a demo chat with their team and see if it's right for you and your practice. And again, I'll encourage you to head over to the evidencebasedchiropractor.com and check out MD Connection. We make it really easy for you to build relationships. It is paint by numbers easy to follow. It's just the. I'm just going to call it out. It's the best way. We have the best product in chiropractic to build relationships with other healthcare providers. So if you want to do it, you want to get results faster than you can get on your own, bar none. And you'd like to get results if you're not getting any results and join the MD connection. It's affordable, it's easy and you can get started literally today. Other than that, I want to say thank you so much for being a chiropractor. Have a fantastic week in practice and I will talk to you soon.

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Sam.