Improve Flexibility with Research-Supported Stretching Protocols
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Welcome to the huberman in lab podcast, where we discuss science and science space tools for everyday life. I'm Andrew huberman and am a professor of neutral logy and optimal gy at stanford school of medicine. Today, we are going to discuss the science and practice of flexibility and stretching flexibility and stretching our topics that I believe do not receive nearly as much attention as they deserve.

For most people, the topics of flexibility and stretching bring to mind things like yoga, injury prevention or maybe even condor's ism. But IT turns out that flexibility and stretching, our features that are built into our basic body plan, Young children, Young animals and adults, and indeed older children and animals, all stretch and all have some degree of flexibility. IT turns out that having flexibility and our ability to stretch and the interaction between stretching and flexibility are fundamental to how we move our ability to learn new movements, indeed also to prevent injury or repair injuries and to offsetting and reducing inflation tion throughout the body.

In fact, today i'm going to share with you a remarkable set of studies that show that stretching can actually adjust things like tumor growth. This is work that was done by one of the major directors of the national institutes of health. So today's discussion will start with a description of the mechanisms, literally, the cells and the connections from nervous system that mediate flexibility and stretching.

And I promised that i'll make that information accessible to you, whether or not you have a biology background or not. Then with that information in hand, i'm going to present to you what the scientific literary says about the best times in ways to stretch everything right down to the detail, how long to hold the stretch where they're not to hold a stretch at all because IT turns out there multiple kinds of stretching. So you can imagine you have stretches where you hold the stretch for a very long time and use as little momentum as possible. And then there's also what's called dynamic and ballistic stretching, where you're literally swinging your limbs, trying to increase the range of motion.

I will explain the science and application of flexibility and stretching in the context of sports performance, whether not you are engaging in cardio, accused exercise or resistance exercise or both, whether not you're competitive, athlete or simply recreational exerciser, as I am, whether or not you are trying to increase your range of motion and flexibility for longevity purposes, or whether not you're trying to do IT in order to access different parts of your nervous system because they'll soon learn today that your ability to improve flexibility and deed to engage in specific stretching exercises can actually be used to powerfully moderate your ability to tolerate pain, both emotional and physical pain. So this thing that we call flexibility and stretching is actually a vast landscape. We're going to simplify and organize all that for you today.

And by the end of today's episode, you're going to have a number of simple, easy to apply tools that are grounded in the best scientist research that you can apply for your specific goals. Before we begin, i'd like to emphasize this podcast is separate from my teaching and researchers at stanford. IT is, however, part of my desired effort to bring zero cost to consumer information about science and science related tools to the general public.

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I started using the waking up up a few years ago because even though i've been doing regular meditation since my teens and I started doing yoga n eja about a decade ago, my dad mentioned to me that he had found an APP turned out to be the waking up APP, which could teach you meditations of different durations, and they had a lot of different types of meditations to place, to bring your body into different states, and that he liked IT very much. So I gave the waking up up a try. And I too found IT to be extremely useful, because sometimes I only have few minutes to meditate, other times have longer to meditate.

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Let's talk about flexibility and stretching. Before we talk about the practices of flexibility and stretching, like to just highlight some of the features that are already built into your nervous system and into your body that allow you to be flexible. Some of us feel tighter than others, sometimes in specific limbs or areas of our body.

Some people feel really loose and limbo. Some people even have what's called the hyper flexibility. I've, for instant, have a relative that can take her fingers and bend them back to the point where they touched her wrist.

And IT always makes me cringe a little bit. But he can do that without any pain. SHE seems to have some hyper flexibility in her joints. I do not have that feature. Some of you may find that you are more flexible than others naturally, and some of you might be thinking you don't need to build in additional flexibility. Well, think by the end of today is is episode.

You'll realized that almost all of us can benefit from having some sort of understanding about flexibility and having some stretching protocol that we incorporate into our life, if not just for physical performance reasons and for postal reasons, then also ford cognitive and mental reasons. And i'll be sure to clarify what all of that means right now. I'd like to take a moment and just highlight the flexibility that you already have.

For instance, if you were to move your ARM behind your torso a little bit and then sort of let go or stop exerting any effort in doing that, you would find that the limb would return more less to opposition next year. Torso least, I would hope. so.

Why is that? IT turns out that there are aspects of your nervous system, aspects of your skeletal system, aspects of your muscles and aspects of the connective tissue that buds all of that together, that trying to restore a particular order or position to your limbs and your limbs relative to one another. So that reflects a very specific set of processes that IT turns out on the same set of processes that you use when you are trying to enhance flexibility and stretching.

So I like to just take a moment and review the basic elements of nervous system muscle, connective tissue and skeletal tissue bone that allow for flexibility and stretching. And here we can point to two major mechanisms by which your nervous system, neurons, meaning nerve cells, communicate with muscles, and those muscles communicate back to your nervous system to make sure that your limbs don't stretch too far, they don't move too far such that you get injured. And in addition to that mechanisms that ensure that you don't overload your muscles too much with weight or attention or with effort and damage them that way, because IT turns out that the second security mechanism of making sure you don't overload muscles can be leverage toward increasing your flexibility almost immediately.

That's right. There are protocols and tools that i'll share with you that are going to allow you to vastly improve your flexibility over time, but there are also mechanisms that allow youtube quite significantly increase your degree of flexibility in a very short period of time in within just a few seconds. So let's establish some of the basic.

Biological mechanisms. In time we talk about biology or physiology, we're going to talk about structure, meaning the cells and their connections and functions, what they do. There are just a few names to understand. You do not have to memorize these names.

The important thing that i'd like you to know is that flexibility in the process of stretching and getting more flexible involves three major components, neural meaning of the nervous system, muscular muscle and connective tissue. Connective tissue is the stuff that surrounds the neural stuff and the muscular stuff, although it's all kind of wave together and breaded together and complicated ways. Some of you may have heard of fashion.

We're going to talk a little bit about fashion today, although it's such an interesting tissue that's really deserving of its own episode. Facial tissue. We're going to talk about some of the stuff that surrounds muscles that really gives you your shape and holds everything together and allows for flexibility to occur.

So here's a key thing that everyone should know, whether not you're talking about flexibility or not. Your nervous system controls your muscles. It's what gets your muscles to contract.

So within your spinal cord, you have a category of neurons, nerve cells that are called motor neurons, to be precise, they are lower motor neurons because they are in your spinal cord. Call them lower to distinguish them from the motor neurons that are in your brain, up in your skull. Those lower motor neurons here after i'll just referred to them as modern neurons.

If I want to talk about the other kind of modern ons, i'll say upper modern neons. So if I say modern neons, I just mean the ones in your spinal cord, those motor neons, send a little wires, or set of wires, out to your muscles. And that creates what's called a neuromuscular junction, which just means that the neurons meet the muscles at a particular place.

Those neurons released a chemical. That chemical is called a seto calling. Some of you may heard about a seattle calling before. A seto calling also exists in your brain and does other things in your brain. Mainly, it's involved in focus and attention.

But at the neural mosquito junction, the release of a seto calling from these nerve cells, these neurons, onto the muscles, causes the muscles to contract. And what muscles contract, they're able to move limbs by way of changing the length of the muscle, adJusting the function of connective tissue like tendon and ligament. And for instance, if you're bringing your wrist closer to your shoulder, that biceps muscle is contracting, it's getting short.

I mean, in reality, IT hasn't gotten shorter overall. It's just temporarily shorter. Of course, all of that is controlled by neurons, and it's those motor neurons from the spinal cord that are really responsible for the major movement of your limbs by way of causing contraction of specific muscles at specific times.

So the key thing to take away is that nerve controls the contraction of muscles. Now, within the muscles themselves, there are nerve connections, and these are nerve connections that arrive from a different set of neurons in the spinal cord that we call sensory neurons. The centurions exist in a different part of the spinal cord, and they send a low wire or set of wires into the muscles.

And there's a particular kind of sensory neuron that comes out of your point, accord in into your muscles, which are called spinal neurons. They create, or they actually wrap around muscle fibers and cork screw around them and give of a spring like appearance. If for you and autos out there, these are intros sal connections or neurons, introduction al means within the muscle.

But you really don't need to know that unless you really curious about IT or you're going to become a neuroscientist or you're medical school or something. These spinal connections within the muscle that wrap around the muscle fibers sense the stretch of those muscle fibers. So now we have two parts to the system that i've described.

You've got motorways that can cause muscles to contract and shorten, and we have these spindles within the muscles themselves that wrap around the muscle fibers. And that information is sent from the muscle back to the spinal cord, is a form of sensing what's going on in the muscle, much in the same way that you have neurons in your eye that sends light in your external environment. You have neurons in your ear that sends sound waves in your external environment.

You have neurons in your spinal cord that are sensory neurons that are sensing the amount of stretch in the muscles. What happens is, if a given muscle is stretching really far, those sensory neurons, those spines within the muscle, will activate. And we'll send a electrical potential, literally a bit of electricity along that wireless length into the spinal cord.

And then within the spinal cord, that sensory neuron communicates through a series of intermediate steps, but to the motor neuron and make sure that that motor or on contracts. Now why would that be useful? Well, what this does is IT creates a situation where if a muscle is or is stretching too much, because the range of motion of a is increased too much, then the muscle will contract to bring that lib range of motion into A A safe change again.

Now, what determines whether not a arrange of motion is quoted, quote, safe or not, is dictate by a number of things. It's dictated by things that are happening in this kind of loop of neural connections in the spinal cord muscle. It's also determined by what's going on in your head, literally in your mind cognitive ly, about whether not the movement of that limb, its increasing range of motion is good for you, whether or not you're doing IT deliberately when they're not, it's bad for you.

And then there are also some basic safety mechanisms that are put in there that really trying to restrict our live range of motion. okay. So just to clarify, this whole thing looks like a loop. And the essential components of the loop, r motor neurons, contract muscles, sensory neurons, of which there are a bunch of different varieties. In this case, what we're call in the spines are sending stretch within the muscles.

And if a given muscle is a longing because of the increased range of motion of a hymn, those sensory neurons send an electrical signal into the spinal cord such that there is an activation of the motor neuron, which by now should make perfect sense as to why that's useful. IT then shortens up the muscle. IT actually doesn't really short in the muscle that contracts, the muscle that brings the limb back into a safe range of motion.

Okay, so this process is very fast. He was designed to keep your body together and save. It's designed to make sure that you don't, you know, take your ARM and swing IT behind your torso and IT just goes all the way back to the middle of your back.

And unless you're a consortium st, you've trained that kind of level of flexibility. That would be terrible because I could provide a lot of damage to the muscles, into the connective tissue and so forth. So that's one basic mechanism that we want to hold in mind.

This idea of a spinal that sends a stretch and can activate contraction of the muscles and short in the muscles, the next mechanism I wanted describe, and once again, they're only two that you need to hold in mind for this episode. The other mechanism has a lot of the same features as the one I just describe, bed. But IT has less to do with stretch.

In fact, IT doesn't have to do a stretch as much as IT has to do with sensing loads. So at the end of each muscles, you have tendence typically. And there are neurons that are closely associated with those tenders that are called golden tender organs, right? These are neurons that are sensory neurons that sense how much you load is on a given muscle, right?

So if you're lifting up something very, very heavy, these neurons are going to fire, meaning they are going to send electrical activity into the spinal cord. And then those neurons have the ability to shut down, not activate, but shut down modern ons and to prevent the contraction of a given muscle. So for instance, if you were to walk over and try and pick up a wait that is much too heavy for you, meaning you could not do IT without injuring yourself, and you start to trying hear that weight off the ground.

There are number of reasons why you might not be able to lift IT, but let's say, you start to get IT a little bit off of the ground. You start to get some force generate that would allow IT to move, but the force that you're generating could potentially rip your muscles or your tendence off of the bone, right? That I could disrupt joints like terror games.

Well, you have a safety mechanism in place. These golgi in organs, these gt. OS, as they're called, they get activated and shut down the motor neons and make IT impossible for those muscles to contract.

okay? So on the one hand, we have a mechanism that senses stretch and can figure out when stretch is excessive. And when the system detects that stretch is excessive, IT activates the contraction of muscles.

And then we have a second mechanism that senses loads. And when tension or loads is deemed excessive, buy these circuits. And remember, these circuits don't have a mind, they will go. This is excessive. They just sense loads.

And when those loads exceed a certain threshold, well then those gt s as golf ten, in order, send signals into the final cord that shut down your motor neurons, ability to contract muscles so that you no longer can lift that heavy load. So both of these are protective mechanisms, but both of these can be leverage in a very logical way and in a very safe way in order to increase your lib range of motion. So there are couple of things I want to point out before going a little bit further into how your nervous system controls flexibility and stretching.

And those key points are the following. There are now dozens, if not hundreds, of studies that show that a dedicated stretching practice can improve lime range of motion. Now for many of you listening, you're probably say duh.

But I think it's important to point that out that a dedicated stretching practice can increase limb range of motion. And as you will soon learn, there are specific mechanisms that can explain that effect. The second point is one of longevity.

And when I say longevity, I don't necessarily mean late stage aging. We all undergo a decrease in in range of motion unless we do something to offset that decrease. And the current numbers vary from study to study.

But if you look and mass, you look at all of those studies and what you basically find is that we start to experience a decrease in flexibility from about age twenty until about age forty nine. That's pretty dramatic. And then of course, IT will continue after age forty nine, but basically, it's a ten percent decrease every ten years.

So we could say it's a one percent decrease per year, although it's not necessarily linear. What do I mean by that? Well, it's not necessarily that on your twenty first birthday.

You are one percent less flexible than you were on your twenty years birthday, and that decreased by one percent per year. Some of these changes can be non linear. So you can imagine the person who's doing just fine in terms of flexibility between twenty and thirty, and then they get to thirty two.

And suddenly we've lost five percent of flexibility. Now of course, there will be a ton of lifestyle factors. If your regular practice of yoga, if you have a dedicated stretching practice, if you're doing other things to improve your muscle contraction abilities, you're doing resistance training, IT, turns out, can actually indirectly improve flexibility.

There are a number of different factors, but the key point is that maintaining some degree of flexibility, and maybe even an enhances range of motion and flexibility, is of immense benefit for offsetting injury provided is not pushed too far. There are a number of people who have pushed their in range of motion so far that they experience all sorts of injuries, both acute, chronic injuries. Today will also talk about how to avoid those scenarios.

okay. S so we've established there are mechanisms within the spinal cord, muscles and connective tissue. Those remember, it's the modern ons, the spindles, the goos, and of course, the muscles themselves and connective tissue tendence, but also other forms of connective tissue that established whether not a limb is going to stay within a particularly range of motion or not, and whether not a limb is going to be allowed by the nerve system to pursue or handle a given load, a given tension.

There are also mechanisms that arrive to the new molecular system from higher up in the europe system from the brain. And those mechanisms involve a couple of different facets that are really interesting, and I think that we should all know about. In fact, today i'm going to teach you about a set of neurons that i'm guessing ninety nine point nine percent of you i've never heard of, including you neuroscientists out there.

If you're out there, and I know you're out there, that seem uniquely enriched in humans and probably perform essential roles in our ability to regulate our physiology and our emotional state. So within the brain, we have the ability to sense things in the external world, something we called externs cept. And we have the ability to sense things in our internal world within our body, into reception.

Into reception can be the volume of food and you're gut, whether not you're experiencing any organ pain or discomfort, whether not you feel good and you're gut. And in your organs, that's actually you feel, I feel great, I feel sad, I feel relax. Those are all different forms of interaction tion.

The main brain area that's associated with interpreting what's going on in our body is called the insula in S. U. L. A is a very interesting brain region. It's got two major parts. The front of IT is mainly concerned with things like smell and to some extent vision and to some extent other things that are arriving from the external world and combining with what's going on internally and making sense of that of all that, or at least routing that information elsewhere in your nervous system to make decision.

Like if you smell something good to approach IT, or if you smell bad to avoid in the front of the insula, is really doing all of that kind of stuff along with other brain areas. The posterior insular, the back of the insula, that is, has a very interesting and distinct set of functions. The poster insult is mainly concerned with what's going on with your synthetic experience.

How do you feel internally and how is the movement that you happen to be doing combining with your internal state to allow you to feel, as I like to say, the nervous system mainly batches things into Young, like, oh, this is really good for me. Yet, this is really bad for me, and I need to stop or made, this is kind of neutral OK. So this isn't about food, but we could say, for most stimulating senses, with than not their senses of things, internally or externally, our nerve system is trying to make decisions about what to do with that information.

And so IT mainly batches information into yum. I want to keep doing this, or approached this thing, or continue down some path of movement, or eating, or staying in a temperature environment. Set a or yc.

I need to get to add here. I don't want any more of this. I don't want to keep doing this.

This is painful or reversible or stressful. And then, man, so IT doesn't really matter. I can can stay right here or not.

Young, Young and met. Well, in your poster y insult, you have a very interesting population of very large neurons. These are, exceptionally, our large neurons called van economy neurons.

These are neurons that are, again, unbeknown to most neuroscientists, and they seem uniquely enriched in humans. Chimpanzees have them, and some other large animals have them. So they are found in whales, chimpanzees, elephants and in humans.

But even though we are much smaller than most whales, and even though we are much smaller than most elephants, I mean, remember, there are baby elephants. As far as I know, they haven't bread up like like mini elephants yet. They seem to have a tea cup version of pretty much every dog breed can look that up.

I don't I certainly have mixed feelings about this notion of trying to downsize everything to the point where you could come like the pocket sized bulldog, I think somebody will arrive. I'm not a fan of that kind downsizing of of different breeds, but because they aren't tek up elephants and teek up gorilla t up companions and so forth, most all of those other species are larger than us. They have these when economy neurons, and we have these van economy neurons, but we have in upwards of eighty thousand of these things in our poster in slow, these other species tend to have somewhere in the range of a thousand to maybe ten thousand or so.

Why is that interesting? Well, these van economy neurons have the unique property of integrating our knowledge about our body movements, our sense of pain and discomfort, and can drive motivational processes that allow us to lean into discomfort and indeed, to overcome any discomfort if we decided the discomfort that we are experiencing is good for us or directed toward a specific goal. This knowledge turns out to be very important to keep in mind, because as we migrate this conversation toward the things that we can do to enhance flexibility and stretching, you'll soon learn that there are moments within a stretching protocol where you have the opportunity to either override pain and discomfort to kind of relaxed through IT, push through IT.

There's a decision fork in the road there and i'll tell you fork in the road to take or to say, uh, i'm not going to do that. I'm going to allow these natural reflexes of the spindle, the kick in and just essentially stop me from stretching if a giving lime isn't designed or shouldn't be stretched that far. So i'd like you to keep these a van economy neurons in mind.

I should mention their named van economy, because the guy, constant van economy, that discovered them at the end of the eighteen hundreds, early one hundred hundred hundreds, decided to name the master himself, as many scientists do are certainly the neurologists and and physicians are famous for naming things after themselves. These van economy neurons turn out to be very important to keep in mind as we embark on our exploration of what sorts of stretching practices can be best applied to increase flexibility. Because whether not you undertake a mild, moderate or intense flexibility training, you will no doubt encounter a scenario at some point where you will have to ask yourself, do I can relax into this stretch, or do I try and push through just a little bit of discomfort? And i'll explain how to gage that decision in a very specific, ideally safe way.

And i'll give you some tools that allow you to make that decision in the way that best preserves the integrity of those neural circuits that I describe earlier and can keep you safe. This van economy neurons sit in the exact position that one would want to be able to evaluate what's going on in the body, in particular, what's going on in terms of lib movements, how that relate sore feelings of discomfort. And then there is the other aspect of these van economy neurons, which is that these van economy neurons are connected to a number of different brain areas that can shift our internal state from one of so called sympathetic activation.

So this is a pattern of alertness and even stress, sometimes even panic, but typically alertness and stress to one, also called parasympathetic activation, to one of relaxation. Often times you'll hear that stretching should be done by relaxing into the stretch. Well, what does that actually mean to relax into the stretch? Well, these van economy neurons sit at this junction where they are able to evaluate what's going on inside our body and allow us to access neural circuitry by which we can shift our relative level of alertness down a bit, or a relative level of stress down a bit, and thereby to increase so called paris sympathetic activation, and to literally override some of those spinal mechanisms, even the G T O mechanisms, but especially the spinal mechanisms at the neuromuscular and muscular spinal junction, and in that way, gently, suddenly override the reflects that would otherwise causes us to contract those muscles back.

The reason that's possible is because your brain has those other kinds of mother neurons, the upper modern neurons, that can both direct meaning control and can override lower motor neurons. I'll give you a brief example of this that you've already done in your life and that we all have the capacity for. What i'm referring to is the monotheistic stretch reflects, this is something that every first year neuroscience graduates student learns, which is that if you were to step on a sharp object with a bare foot, you would not need to make the decision to retract your foot.

You would automatically do that, provided you have a healthy nervous system. There are mechanisms in place that caused the retraction of that lib by way of ensuring that the proper muscles contract and other muscles do not contract, in fact, that they fully relax. Okay, so in the case of stepping on a sharp object like a piece of glass or a nail or attack, you would essentially activate the hit flexor to lift up your foot as quickly as possible.

In doing so, that same neural circuit would activate a control of meaning opposite side of the body circuit to ensure that the leg of the foot that's not stepping on the sharp object would do exactly the opposite and would extend to make sure that you don't fall over. All of that happens reflexively. IT does not require any thought or decision making.

In fact, humans without any neocortex, literally, that who are described, or an animal that doesn't have and I say to serve, but I mean lacks of a reba cortex, they can perform that because it's all controlled by circuits that are basically below the brain in in the spinal court. There's a little bit of activation circuits in the kind of deeper parts of the brain, but basically, you don't need to think or decide in order to do that. However, if your life depended on walking across some sharp objects, let's say, let's make you a little less dramatic so it's not like the die hard movie or something.

We have to run barefoot across the glass, although that's a pretty good example of what i'm describing here. But let's say you have to walk across some very hot stones to get away from something that you wanted to avoid. You could override that stretch reflects by way of a decision made with your upper motor neons, your insulin, your cognition, and almost certainly those van economy neurons, which would be screaming, don't do this, don't do this, don't do this, could shuttle that information to brain areas that would allow you to override the reflex and essentially push through the pain, and maybe even, in fact, even not experiences the pain to the same degree, or even at all.

So these van economy sit at a very important junction within the brain. They pay attention to what's going on in your body, paying pleasure at seta, and then includes what's going on with your limbs and your limbs ge of motion. They also are paying attention and can control the amount of activation kind of alerts or commons that you are able to create within your body in response to a given sensory experience.

And as I mentioned before, they seem to be uniquely enriched in humans. They seem to be related to the aspects of our evolution that allow us to make decisions about what to do with our body in ways that other animals just simply can't. Before we go any further, I want to give you a practical tool that you can, of course, use, but that will also give you insight and experience into your muscle, spinal, spinal cord circuit mechanisms.

So what i'd like you to do is, if you're in a proper place to do this, you're going to stand with legs straight, meaning knees not bend, and you're going to try and touch your toes. Or for some of you, that's going to be very easy and you might even be able to put your hands flat on the floor. I don't have that kind of flexibility is pretty y for me to touch my toes.

I don't care if you round your back or not. Although ideally I would say don't round your back, not because it's bad to do so necessarily, but just to try and keep this the same from trial to trial as IT were. So try and get a sense of what your range of motion is in terms of bending over at the waste while maintaining a flat back and trying to touch your toes or even touch the floor.

Maybe again, you can even go hand flat to the floor, maybe even far out in front of you. okay. Now what i'd like to do to stand back up, and i'd like you to contract your quarter steps as hard as you possibly can for about five to fifteen seconds, let's say ten seconds, just to keep things more less Normalized.

This obviously is not super controlled experiment. So to contract your quarter steps, for those who don't know, you're going to extend your lower limb out. So this would be like kicking, although do you too quickly you're going to kick out your your foot, you should feel your quiet ships contract on the top of your thought, and you're going to try consciously contract them as hard as you can OK.

Typically, if you want to point your toe back towards your near shin, that's also going to help somewhat to contract even harder and harder. Okay, so do that for about ten seconds. A lot of you will do this just while standing.

Contract, contract track. Okay, then release IT. And then now go head and repeat that stretch where you're trying to touch your toes or touch the floor. This is, again, relying more or less on hamstring flexibility, among other things. Kay, what most of you will find is that you have an immediate increase in hamstring flexibility or your range of motion has increased.

If you didn't experience that, then I would encourage you to try and contract your quality steps harder and longer, so maybe twenty or thirty seconds, and then try this so called experiment again. Why would contracting your quarter eps allow your hamstring flexibility to suddenly increase? Well, the way that our muscles are organized is such that we have muscles that are in tagish to one another.

So our quarter steps in our hamstrings work sort of a push pull fashion, if you will, they can antagonize one another. So when you move your heel towards your glutes, you are using your hamstring. The hamsters ing obviously also, does other things relate to hit movement.

And when you lift your knee or when you extend your foot and contract your quads ships, you are essentially relaxing the hamstrings. Of course, most movements involved both quarters up in the hamstring in synchrony. And synchrony is really an elegant one.

But here were more less isolating the quarter steps from the hamstringing, at least the extent that I can leverage these spindle stretch mechanisms. So what happens is when you contract your quarter steps hard, you are relaxing or releasing some of the stretch that's occurring in those, introduce al spinal sensory fibers going into your spinal cord. And as a consequence, you're able then to stretch your hamstrings further.

Or we can be more accurate and say that your range of motion about the hamstring and its related joints is greater when you aren't engaging that spinal reflex, which would cause the hamstrings to contract. okay. So if you are somebody who has tight hamstrings, there could be a variety reasons for that.

But part of the reason is likely to be neural. And you can release that neural spinal reflex by contracting the opposite and tagish muslims. In these cases, the watter steps, the same thing that is true and can be leverage for stretching other muscles.

For instance, if you're going to do a try, step, stretch the typical kind of overhead where you grab your elbow and move IT toward the middle of your body with the other using your opposite hand, well, you can do that. And then I would suggest trying to flex your bye p contract, your bip, that is, while doing that. And for most people, you notice a increase in the try set range of motion ability to kind of lean into or to relaxing into or to push that stress stretch.

Excuse me a little bit further now for you physios out there and for those of you that have backgrounds and kaese ology, I want acknowledge, of course, there are other mechanisms that are coming into play. There are actually neural connections within the joints themselves that are providing proper accept of feedback at, at, at. But this is simply to illustrate that part of our range of motion is determined by the spinal mechanisms that I spend some time focusing on earlier.

And indeed, this approach can be leverage toward creating increased liver range of motion, not just for the hamstrings, but for your quarter ery PS. For instance, if you have tight quarter steps, you can do the opposite. You can contract your hamstring very intensely for, let's say, ten seconds or twenty seconds or thirty seconds.

So that would take some conscious ever of bringing your heal up towards your glutes. Um you could do that in a way that you're really trying to contract those muscles hard. You'd have to use some deliberate hamstring activation there, meaning you have to use those upper motor neons and the other aspects of your your upper brain power, as IT were, to try and really contract your hamstring, says intensely as possible.

Then you would relax that, and then you would do your quite step stretch again. And if you did a pre hamstring contraction measured of your quadro p flexibility, and then you did a post hamstring contraction measure of your quarter ship flexibility, almost certainly you would find that, that flexibility had increased. Now of course, the muscle really didn't change much.

The tendance didn't change much. What changed was the patterns of neural activation that we're restricting you from, in the first case, stretching your hamstring or having a to be more accurate, we should say, to having a certain range of motion about to the hamster ing and its related joints. And those break mechanisms were removed.

And of course, then when you contract your ham's during, you're removing some of the neural breaks, the spinal acting as a break and inhibiting that quarter set range of motion. okay. So you can imagine this.

In fact, you can apply this for any number of different muscles, the larger muscles and the sort of by seps dry steps and chemistry quarter steps that urts serve the simplest place to think about this to apply IT. But in theory, and indeed in practice, IT really works for all the various muscle groups, is just sometimes harder to access these so called tagging tic muscle groups. Now we should take a moment and just discuss what actually happens as we get more flexible in the short term and long term.

I just mentioned what happens in the short term. Clearly, those don't involve length. Threading of the muscles is not like the muscles slide along the bones or that the tendance really stretch out that much more than they had prior to that kind of, you know, exercise.

But IT is the case that if people stretch consistently over a given period of several weeks or more that there are changes in the muscles. This gets a little bit tRicky in terms of nominal creature and I just want to highlight that because I think a number of people um get frustrated uh and confused. In fact, when we talk about muscles getting longer, that the whole concept of a muscle getting longer isn't really in keeping with reality, but there are elements within the muscles that can change their confirmation.

So to get a little bit detail here, and we won't spend too much time on this, but I just want to acknowledge this, for those who either interested in our physiology and relates to flexibility, you you have your muscle fibers, and then you have your so called milo fibre. So you can imagine of a single fiber. That fiber, of course, will get input from those modern neurons.

And then within those fibers, you have what are called circle meers. And you can kind of think about circle meers as little segments kind like the segments of bamboo. If you ever look at bamboo, it's not just one big stock.

It's got those little out paches along the way that um GTA break up the what would be just one big stock of bamboo into different segments. But they are all connected. The sarcasm are somewhat like that.

And within the circle years, you have a couple of different components. One thing is called Mason, which is like a thick layer, and then the others act in and those are interdigitated ors. We say the kind of connected to one of the kind of you put your fingers together from your two hands, if you know, you put your fingers in between one another.

That's intergalactic erly interdigitated in this case. So punk intended. And that maison and act in kind of move relative to one another. And they have a lot to do with your ability of contract muscles. When we stretch muscles, when we go through a stretching practice, there are a number of things that changed, some neural, some related directly to connect tissue, but also IT appears from really nice work, mainly done from the guille university.

Provide a link to a couple of these studies, if you want to dig in there more deeply that change the confirmation, the relative size and spacing of some of these things like sarcumstance in the way that mayson and act in kind of work together. But we don't want to think of muscles as in thinking. We can, however, think about the resting state of a muscle being slightly different, or indeed very different.

Then the resting state of a muscle of somebody or of a limb that has not undergone regular flexibility training. So that as much time as I want to spend on that because we could spend an entire hour getting right down into the details. But I do want to emphasize, however, that muscles have different parts. They have fibers, they have circ, they have miles, and they have act in. But the idea of making our muscles longer that reflects the number of processes that occur basically within an an existing muscle lane are the length of our muscle bells and where our insertions are relative to our connective tissue limbs is genetically determined.

Right some people have, for instance, a biceps that goes all the way from the cricket, the elbow up to their shoulder right um and some people can you know if they would have put their army in a nine degree angle, could put two or three fingers between their bicycles and their elbow, they have a we can say a shorter biceps, relatively shorter. Now the reason I mention these highly detail cellular mechanisms is because as we start to embark on different protocols for using stretching to increase flexibility and range of motion, we need to ask ourselves, what is preventing our ability to extend range of motion? Is that the spinal right is that because the muscle is stretching too much, often times IT can be because of that end, or because of a sense of pain or simply a sense that the muscle is not in a position that it's been in before that's unrelated to pain or to spend the activation.

And often times IT can be related directly to these changes in the confirmation of Mason and acting and within the context of the circumstance. And of course, you can't peer into or sense or individual circle ers. However, you do have neurons that innovate these areas and that send that sensory information back to the spinal cord, up to your brain to interpret.

So you will find that as we move along, there are specific adjustments that you can make at the both the macro o level, meaning how much movement to insert into stretching right, is there can be a static or dynamic, even a ballistic stretch, or for instance, at the row level that even just a slight submillimeter or millimetre increase in the stretching of a given muscle and the related tissues can translate into an increased range of motion performance. As a quick book relevant aside, I thought i'd share with you something useful that's also grounded in this notion of tagish muscles. So for those of you that you resistance training, whether not with body weight or with physical weight or machines, what have you?

You may found that if you, let's say what to do, three sets of a pushing exercise. So this could be push ups, this could be bench presses, this could be shoulder presses, something in that sort. And then later in the workout, you were to do, let's say, machine pulled downs, or pull ups or chin ups of some sort of a pulling exercise.

Typically what you would find is if you were to do what's often called straight sets, so you would do three sets of push ups, let's say, with two minutes of rest in between, that you might be able to get a certain number of repetitions on the first set. Just for sake of example, let's say you can get ten repetitions on the first set and then you get eight repetitions on the second set, and then you get six repetitions on the third set with two minutes in between. And then you would move on at some point to your pulling exercises.

And similarly, let's say you were doing chinese PS were pull down and you would get ten repetitions, rest two minutes, eight repetitions rest two minutes and six repetitions. Okay, fine. Well, typically what people discover is that if they never leave, they're pushing and pulling exercises, provided they do that for muscles that are in tagish to one another. So in this case, pushing with the chest, shoulder and trips for the pushing exercises and pulling with the back in bioethical, of course, the other muscles involved as well.

But because those muscle groups are at least in part in tagging tic to one another, what people often find is that if they were to say, do their pushing set yet ten repetitions, then move to a pulling set after just, say, sixty seconds, and perform that polling set, then go back to the pushing set, then go back to a polling set, push, pull, push, pull. In other words, interleaving their sets, even if they were to maintain the same amount of rest between sets of pushing and sets of polling, what they discover often is that the drop in the number of repetitions that they get is somewhat offset. So rather than get ten, eight, six, as IT were with a straight set, IT will be ten, nine, eight.

So what this means is not that you're increasing the total rest time to four minutes between sets because then of course, IT wouldn't be equivalent, but rather that while maintaining the same amount of rest between sets for the same muscle group, by going from push pull, push pull of antagonistic muscles, you're able to have improved performance. And the reason for that has everything to do with what we were describing before, which is that typically, if you were to do push set rest, push set rest, push set rest, well in between those sets. And in fact, actually during those sets of pushing the polling muscles that would be involved in the chin ups are pull down that are actually relaxing or at least are being released of some tension, including the activation of the spindles, among other things.

So that's a long winded way of saying the interleaving pushing pull of tagish sets can leverage some of the same neural circuits that we're talking about leveraging for sake of increasing flexibility. Now I offer this to you as a tool that you can try a one of the chAllenges with using this tool, however, is that you often have to occupy multiple sites within the gym. You know, if you're doing this at home and you have your own gym, that's one thing.

If you're doing this in a gym, we have multiple pieces of equipment, then you become that person who has essentially taken over some small corner or multiple corners or machines within the gym. And often times you'll find that you walk back to a machine or you walk back to a given resistance exercise. And someone has now taken IT over.

And the whole thing can be thrown off. So IT takes a little bit of orchestrating in order to do properly. But in general, what people find is that this can allow you to enhances performance overall of these individual movements again, while maintaining the same amount of rest. And even if you choose not to do this, I engage you to pay attention to this as a concept because, again, it's leveraging this idea of antagonistic muscles, flexes and extensors tagish neural relationships between the spinal cord mechanisms that control one set of muscles and activating those muscles, allowing the opposite and tagish muscle to relax and therefore to perform Better on its next set.

So now I D like to shift to the question of what types of stretching can and should we do to increase liver range of motion, if our goal is to do that in the most efficient way possible? Because I realized that most people don't have, and less amount of time to dedicate to a stretching practice. And even for those of us that do, i'm sure that you want to get the most outcome for a given effort.

And what are the modes of stretching that are going to allow us to increase our flexibility and liver range of motion most safely? Now there are number of different types of stretching or methods of stretching. Broadly defined.

We can describe these as dynamic, ballistic, static. And what's called P, N, F. stretching. P, nf stands for appropriate active normosang lar and IT involves in leverages many of the mechanisms that I described you earlier. The first two that I mention, dynamic and ballistics stretching, both involve some degree of momentum and can be distinguished ed from static and p nf types stretching now to distinguish dynamics stretching from stretch, like to focus on this element of momentum, both involve moving a lym b through a given range of motion.

In dynamic stretching, however, IT tends to be more controlled, less use of momentum, especially towards the end range of motion, wherein ballistic stretching there tends to be a bit more swinging of the limb or use of momentum. So I invite you to visualize what dynamic and ballistic stretching might look like in your mind. You can even try IT.

If IT safe for you to try IT, you could imagine your swinging your arms up overhead as much as possible, bring IT down. I'm doing this because i'm seated is kind of ridiculous movement to do well seated, or perhaps at all. But for instances you can see dynamic and ballistics stretching anytime someone, for instance, is holding on to something with one ARM, or maybe not holding on and swinging out there their foot.

So essentially getting movement about the hyp joint. And you'll notice that some people raise e IT up and pause IT and bring IT down. That's one form of dynamic stretching.

Whether others will swing IT up and get sore, let IT Carry itself a bit further to the momentum at the top of the movement, and then just let IT drop back down or maybe even control the descent. There is an enormous range of parameter space here or variables that one could imagine. And there's just simply no way that we could subdivide all those.

But again, dynamic and ballistic stretching both involved movement. So we have to generate some force in order to create that movement, ballistic stretching involving a bit more momentum or sometimes a lot more momentum, especially at the end range of of motion. Now both of those are highly distinct from static stretching, which involves holding the end range of motion to minimizing the amount of momentum that's used.

So to stay with a simple example that where we are all now familiar with from our earlier discussion, slowly bending over at the waste and trying to touch your toes or putting your hands to the floor, and then holding that in position before coming up in a slow and controlled way, such that you reduce the amount momentum to near zero. Would be one example of static stretching. Static stretching can be further subdivided into active or passive, right? There are different names for these kinds of approaches.

You can hear about the underside approach or the johna approach. You can look these sorts of things up online. And again, people tend to name things after themselves.

Some of these are proprietory relia specific programs. I'm not focusing on those. Others come to be named after the physiologist or the practitioners that initially popularized them. As is always the case, there's always a naming and renaming and claiming of territory with these things for the time being.

I'd like to just emphasize that static stretching can be both active where there is a dedicated effort on the part of the stretch you to put force behind the hole to kind of extend or literally to extend the range of motion. And then there's also passive static stretching in which is more of a relaxation into a further range of motion. And that can be a subtle distinction.

And there are other ways in which we can further distinguish active and passive static stretching. But nonetheless, static stretching involves both those types developments, active and passive, but is really about eliminating momentum. And then there's the P N, F, A proper accept of of the moscow facilitation.

And proper action has several different meanings in the context of neuroscience and physiology to just keep IT really simple for today, proprioception involves both a knowledge and understanding of where our limbs are in space and relative to our body, typically relative to the midline. So the brain is often trying to figure out where are our limbs relative to our midline down the center of our body. And we know where our limbs are based on so called proprioception feedback.

So that feedback that comes from sensory neurons right now, you know what century neurons that are essentially monitoring or responding to events within the joints, the connective tissue and the muscles, and within the deep components of the muscles, like the spinal reflex, and within attendance, like the gt. O, the golgi, tend in organ. So p, nf types, stretching leverages these sorts of mechanisms, these, these neural circuits, by way of, for instance, you would lie on your back.

And if your goal is to increase your hamstring flexibility and the flexibility and range of motion of other related muscle systems, you might put a strap around your ankle and pool that muscle, where I should say, excuse me, that lib towards you are going to pull the muscle towards you, going to pull that limor ankle towards trying get IT or back over your head, and then progressively relaxing into that, or maybe even putting some additional force to push the end range of emotion, and then relaxing IT, and then actually trying to stretch that same lamor, increase the liberate emotion without the strap. right? Sometimes these are assisted by other people, so people will even use loads.

Sometimes they even use machines. There are number of different apparata that have been designed for this. Sometimes IT will involve a training partner.

There is a huge drage of p. nf. Protocols, and those protocols can be done both by oneself, with or without straps, with machines, with actual weights or with training partners.

If you're interested in the variation of exercises to, say, target your hamstrings versus your quadriceps, versus your shoulders, versus your chest muscles and set your neck muscles and so on, there is an enormous range of information on dynamic, political, CS, static and p, nf stretches for all the various muscle groups. And I should say there are some excEllent books on those topics. There are also some excEllent videos on youtube and elsewhere.

Nowadays, it's pretty easy to find sizes that allow you to target specific muscle groups. Again, I encourage you to be safe in how you approach this, and I would encourage you also to pay attention to the information that soon follows as to what sorts of protocols one would use to apply those exercises. But the number of exercises and the availability of those exercises for targeting different muscle groups with these four different kinds of stretching is both immense and fortunately, thankfully, immediately accessible to all of us, often at zero cost.

So specific exercises to target specific muscle groups aside, we've now establish that there are four major categories of stretching, at least those are the four major categories i'm defining today. And we can further divide those categories into which are the ones that are going to be most effective for increasing range of motion in the long term, not just in one individual session. And there have been a number of studies expLoring this.

I can list out at least for and will put those for as a kind of a cluster under one heading in the shown out captions that arrive at essentially the same answer, which is that for increasing in range of motion, IT does appear that static type, including P, N, F. But static type stretching is going to be more effective than dynamic and ballistic stretching. So at least in my mind, this is good news.

Why is the good news to me? Well, well, dynamics, politics stretching can be immensely useful for improving performance of specific movements, in particular in the context of particular sports like tennis or in sprinting. Or Frankly, for any sport, they do Carry with them a certain amount of risk because of the use of momentum.

So you don't need to be highly trained in order to perform them. In fact, there is a place and we will describe when one would want to apply dynamic or ballistic stretching. I'll just give away for now. I think that most physios out there and certainly the ones that ice boat to doctor andy galpin, doctor Kelly started and a few others, point to the fact that doing some safe, dynamic and ballistic stretching prior to, say, a resistance training session, or maybe even in prior to a cardiovascular training session, can be useful both in terms of range of motion effects and in terms of neural activation effects.

And I want to use the words warm up, because warming up is typically associated with increasing core body temperature, as IT should be, but for engaging the neural circuits and becoming familiar ized with the neural circuits that you are about to use in other movements, while also increasing the range of motion of the joints involved in those movements, so that you can perform them more safely and more confidently. So i'm certainly not saying I want to repeat. I'm certainly not saying that dynamic and ballistics stretching are not useful.

They absolutely are. But in terms of increasing in range of motion in the long term of be truly becoming more flexible as opposed to transiently more flexible, static stretching, which includes p nf, appears to be the best way to go. So if your goal is to increase your little range of motion for a given muscle group, of perhaps for all muscle groups, although you can imagine that would be pretty tough.

I mean, you going to spend time, I could imagine working on your tune, muscle control or necked muscle control and every muscle control. But most of us want to reduce so called tightness in air quotes and increase in range of motion for certain muscle groups. And IT appears that the best way to do that is going to be static stretching of some kind, which raises the question of how often to do that static stretching and how long to hold those static stretches.

And we can also ask the question, we should ask the question, where to hold those static stretches is is always a good idea to hold those static stretches at the end or the point of maximum range of motion. We're going to address that now there's some terrific science around this, a slightly older study, but a powerful one because IT provided a foundation for a lot of subsequent work, which basically served to just confirm the answer they got. Here is a study from bandy at all. The title of this study is the effect of time and frequency of stats stretching on the flexibility of the hamstring muscles.

The study involving ninety three subjects, so sixty one men, thirty two women, ranging in age from twenty one to thirty nine years abroad demographic, who had limited hamstring muscle flexibility here on paraphrased ing and randomly aside to one of five groups so the four stretching group stretched five days per week um for six weeks the fifth group were served as a control did not stretch the results clearly show that quote, the change in flexibility appear to be dependent on the duration and frequency of stretching. This is great. This tells us that stretching for a given amount of time scales with the amount of in range of motion improvement that one will see.

There were many interesting findings within the study, but the one that i'd like to highlight most is, quote, the results of the studies suggest that a thirty second duration is an effective amount of time to sustain a hamstring muscle stretch in order to increase range of motion. No increase in flexibility occurred when the duration of stretching was increased from thirty seconds to sixty seconds or when the frequency of stretching was increased from one to three times per day. okay.

So when I was starting to lay down some parameters, what this study reveals and what subsequent studies tell us and we will get into those subsequent studies, is that ideally one would do static stretches that are held for thirty seconds, perhaps more in certain instances, and explain when that can be useful. But here, holding those stretches for more than thirty seconds did not turn out to be additionally useful. So if you're going to stretch your quarter set, for instance, and you're going to hold that stretch in static faction, remember not using momentum and you can use the mental tricks of either trying to push through the pain, which I don't recommend necessarily, I think that makes us prone to injury or to relax into the stretch, but none the less providing some force, typically with the with the hand in order you pull your ankle back.

If you're doing a quarter step stretch, some people might do this on the edges of a sofa. Remember there a lot of different exercises in ways to do this that you can explore elsewhere, while holding that start stretch for thirty seconds appears to be sufficient to stimulate an increase in limb range of motion over time. Again, these are protocols that we're used repeatedly over time and will talk about how often to repeat them in order to get maximum effect.

But thirty second holds for static stretches is the number that I think we want to focus on and that most of us are going to want to utilize. So now let's explore how many sets of static stretching one ought to do in order to get a maximum range of motion improvement while not placing us into a system that's gona create injury, nor a situation where we have to be constantly stretching throughout the day, because, again, most people don't have time to do that. This issue of sets is an important one in the context of cardio equal exercise.

We've talked about the data that support the fact that doing at least one hundred and fifty, and ideally as much as two hundred minutes per week of zone to cardiovascular exercises that is very useful for cardiovascular health and for other aspects of health. And of course, the other aspects of cardio aspar exercise that could be layer onto and into that, that can be useful like ninety second maximum springs that at the discuss this a lot in the episode with doctor anny galpin and on our episode about endurance. And we also talk about sets in the context of strengths and hypertrophy building, building muscle size and or strength in the east ode about that, and in particular the episode with doctor and he alpin.

And there we could also arrive at some promoters, and it's goten to vary, of course, betwen individuals depending on how hard you train, whether not you take that to failure your repetition range at a but in the context of strength and hypertension y building, we arrived at a approximately six, maybe as many as ten sets per week, poor muscle group. Some of that work is done as direct work to a given muscle group. Some of that work is indirect.

So doing certain polling exercise, of course, will target the latin and dorsey muscles, but also the bip. So if you that doesn't necessary mean you have to do ten sets for the bytes and for the lads, sometimes you're getting some indirect work at that. All of that was delineated in the episode doctor and he galpin. And we arrived at those numbers of sets according to the same criteria that we will apply here. What is the minimum number of sets both to maintain end to improve a given motive performance, strength in hyperdrive phy or cardiovascular health, again, to either maintain or improve.

And we can do the same thing for improving or maintaining range of motion because, as I mentioned earlier, the data point to the fact that if we don't do some dedicated work to improve range of motion over time, we will lose our flexibility and little range of motion over time just by virtue the fact that we're not doing anything to offset that. So whether not you want to maintain, reestablish or gain in range of motion, static stretching of holds of thirty seconds appear to be best. Now the question is, how long should you do that? And how many sets should you do that? And how many times a week should you do that? And to answer those questions, when I turn to what I think is a really spectacular review, this was a review that was publishing the year twenty eighteen.

So it's fairly recent. First author Thomas IT, won't Thomas? Last author, pala. We will put a link to this in the show. Note caption the title of the paper is the relation between stretching typology and stretching duration, the effects on range of motion, a very straightforward title.

This is a review article that explored a number of different studies, had criteria for whether not those studies could be evaluated in the context of the questions here, has some quality standards and some other standards that they applied, and basically winter down large collection studies to a remaining twenty three articles that were able to be considered, quote, eligible and included in the quantity synthesis done here. So key points from that quantification and synthesis done in this paper, first of all, and I quote, all stretching typologies, showed range emotion improvements over a long term period. However, the static protocols showed significant gains with A P value less in point of five, which means a probability that cannot be explained by chance alone when compared to ballistic or p nf protocols.

So again, what we're hearing is that static stretching is the preferred mode for increasing in range of motion, although here they make the additional point that static stretching might even be superior, not just to ballistic stretching, but also to p nf protocols. Because before you may recall, there was a distinction between ballistic and dynamic and static and p. nf.

And so here IT appears again that static stretching is sort of rising to the top of the list as the optical approach relative to all other stretching approaches, at least in the context of increasing lives of motion. The authors go on to say, time spent. Stretching per week seems fundamental to illicit range of movement improvements when stretches are applied for at least or more than five minutes per week.

Okay, this is critical. This is not five minutes per stretch, remember, thirty seconds per static stretch, but at least five minutes per week, whereas the time spent stretching within a single session does not seem to have a significant effects for range of motion gains. If this is getting confusing, i'll make sure that you soon understand exactly what we can export from these conclusions.

The data indicate the performing stretching at least five days a week. Now some of you may already be growing for at least five minutes per week OK. So five days per week, that's a lot, but at least five minutes per week.

Five minutes per week is not that much. Using statics stretching maybe beneficial to promote range of motion improvements. okay. I've read this study in detail now. The highlight again, the reduction in flexibility that occurs from twenty and forty nine years of age and so on, how a cute belt of short term stretching up to three weeks can improve stretch tolerance.

I think that's a key point that in the short term, the first three weeks of embarkation on a stretching and flexibility program, much of the improvements come from the short term neural improvements that we talked about before of inhibiting the spinal reflects and so on, and also a stretch tolerance, a comfort with doing the movement and maybe even a comfort in overriding some of the pain mechanisms. I'll talk a bit more about that in in just a bit. And the particular utility of yoga, something that I don't often practice, but that after reading this article that mention a little bit, i'm considering perhaps taking up some form of yog protocol.

Now i've already highlighted some of the key takeaway from the study, namely that we need to get at least five minutes per week of static stretching per muscle group. And based on the previous paper that we talked about, we need to divide that five minutes into set of thirty seconds each. And as I mentioned earlier, IT doesn't seem to be the case that you can do all of that in one day.

Unfortunately, IT does seem important that the frequency of stretching practice distributed throughout the week is important. So let's talk protocols. We are now talking about doing static stretching, so holding, so limiting momentum and holding a stretch for thirty seconds. We're talking about trying to achieve five minutes per week of those static called, but that we can't do IT all in one session because the frequency of sessions distributed throughout the week correlates tes with the improvements and liming ge of motion.

So what this means is that we should probably be doing anywhere from two to four sets of thirty second static hold stretches, five days per week, or some very in there of, and I do say some very in thereof, because IT turns out that even though there was that earlier study that we talked about, that holding a stretch for more than thirty seconds, in that case, sixty seconds didn't turn out to be additionally beneficial. IT appears that if you do hold those stretches for sixty seconds per static stretching set, for instance, you can get away with stretching fewer days per week overall. So in order to make this as clear as possible, because I do realized there are a lot of parameters, and you might be asking, why didn't you just make me a list of the exact things I should do? Well, IT doesn't work that way.

Because once you understand the mechanisms and once you understand your particular goals, this information is designed for you to be able to construct to a stretching program that is tailor to your specific goals. If I just gave you the stretching program that I am doing, or I should say that i'm soon to be doing, because I am soon to be doing one based on the research for this particular episode, well, that wouldn't beneficial for you because, for instance, if you have very flexible hamstrings but not very flexible quarter steps, or are you are somebody who is engaged in sport or not engaged in sport, what you need to do is going to vary somewhat. So what would the effective stretching protocol look like? We're all trying to improve liverage of motion for different limbs and different muscle groups.

But just by way of example, that's because the one we've been using, let's talk about hamstrings for the time being. This could, of course, be applied to other muscle groups. Let's say you want to improve hamstring flexibility and liming ge emotion about and around the hamstring and involving the hamstring, you would want to do three sets of static stretch for the hamstring.

Again, easy to find such exercises on the internet. You would do that by holding the stretch for thirty seconds, resting some period of time, and doing IT again, holding for thirty seconds, resting some period of time, and then holding IT for thirty seconds. That would be one training session for the hamstringing.

I have to imagine that you'd probably want to stretch other muscle groups as well in that same session. Although at least as far as I could tell, there were snow data pointing, the fact that you couldn't do your hamstring stretching one part of the day and your quartz ships stretching another part of the day. But presume ly, you're going to want to combine your flexibility training in into one single session.

So three sets of thirty seconds each get ninety seconds, and you would do that ideally five times a week or maybe even more because IT does seem like frequency distributed throughout the week as important parameter. Now one thing that we have not highlighted, or at least described, is how long to rest between stretching sets. And despite my efforts, I could not find research back information that pointed to whether not thirty seconds of rest for every thirty seconds stretching or sixty seconds last for every thirty second stretching was ideal.

I think it's reasonable to assume that doubling the amount of time for the interleaving rest would be appropriate, or at least doable, if anyone out there has knowledges about rest between stretching sets and has some physiology or some biology or some experiential information as to why a given ratio of duration of static stretch to rest in between static stretch sets ought to be used, please put IT in the comments on youtube. There would be a terrific way for us to get that information. I'd love to do any follow up to links that you provide and so on.

But now we're starting to build into a protocol that is backed by the scientific data. Three sets of thirty seconds of hall done five times or maybe in six times per week. One thing that did show up in my exploration of the peer reviewed research is this notion of warming up for all this.

We have been talked about that yet. In general, to avoid injury, it's a good idea to raise your core body temperature a bit before doing these kinds of stretches, even these static stretches, which we can sort of ease into and don't involve ballistic movement by definition. And the basic take away that I was able to find was that if we are already warm from running or from weight training or from.

Some other activity. They're doing the static stretching practice. At the end of that way, training your cardiovascular or other physical session would allow us to go immediately into the stretching session because we're already warm, so to speak.

Otherwise, raising one's core body temperature by a bit by doing five to seven, maybe in ten minutes of easy Carter vaso exercise or kala's inc. Movements, provided you can do those without getting injured, seems to be an ideal way to warm up the body. For stretching, we should be warm or warm up to stretch, although those warm ups don't have to be extremely extensive.

And then just by way of logic, doing the static stretching after resistance training or car diva cual training seems to be most beneficial, in fact, and unfortunate, we don't have time to go into this and too much to deal today. I was able to find a number of papers that make the argument that statics stretching prior to cardiovascular training and maybe even prior to resistance training can limit our performance in running and resistance training. I realize that's a controversial area.

You have those who say, no, it's immensely beneficial. You have those who say no, IT inhibits performance. And those that say no, it's a matter of how exactly perform that static stretching in which muscle groups and how you're doing this and how much time in between start stretching in performance.

But to leave all that aside doing, start stretching after some other form of exercise, and if you not, after some form of exercise, after a brief warm up to raise your your body temperature, definitely seems like the right way to go now for some of you out there. And I confess for me as well, doing something five days a week seems like a big commitment, even if that commitment is one to only do three sets of thirty second static stretches. I say this because you've got the warm up.

I generally like to bring a kind of a focus and dedication to a practice. And of course, because when doing these kinds of protocols is likely that you're not just stretching your hamstringing. So it's not just ninety seconds of work with a minute of rest in between, but very likely that also doing quite step stretching and also doing stretching for the shoulder and stretching for the back and the neck and so on.

And so that entire session is going to take some time and five days a week as a pretty serious commitment for most, especially for those of us that don't exercise or do athletics for a living. I don't so there is some evidence from the literature that one can get away with, or I don't even know that we should think about is getting away with, but that one can do longer, hold static stretches of up to, say, sixty seconds, but do fewer total sessions per week. So rather than three thirty second static holes, doing three sixty second static holes and doing those every other day.

And there really has a in a systematic exploration of this, the article that I was referring to just a few moments ago. Um this analysis of the twenty three articles was combined into this enormous a set of tables and some um really quite nice graphs that you're welcome to look at. Since we're going to provide a link to the study, there are a couple of key takeaway that I want to mention that are separate from this issue of how long distraction, how often.

First of all, they describe in their discussion that there were improvements and range of motion independent of whether or not people did static stretching, active stretching, passive stretching, ballistic stretching or P, N, F. stretching. So all of those storms are stretching will improve lib range of motion.

This is essential to point out. And I want to emphasize this static stretching, however, gave the greatest degree of gains in the range of motion. And on average, they saw a twenty point nine percent increase.

But some of the other increases they observed were also quite substantial. So billiter s stretching can also provide some pretty impressive in range of motion improvements. However, they attended to be in the range of here, they point out eleven point six five percent increase, or in the case of p nf, of fifteen percent increase.

So IT appears that the greatest improvements in limbering emotion for your time spent and effort spent is going to be this minimum of five minutes per week to illicit a significant response, with five days being the minimum weekly recommended frequency to achieve significant range of motion improvements. I confessed this was pretty surprising to me when I compare flexibility training to, say, resistance training for strength and hyperdrive phy. I've had the experience, and I know that other people will have the experience.

And I think doctor and he galpin would probably agree that provided one trains hard enough and appropriately that you don't need to train resistance training five days a week in order to get significant improvements in strength. And hypertext y some people might need to, but you can get a lot of positive results in those variables with less frequent training, certainly with three or four days a week of training. And for cardiff asked lar training, i'm not aware of anyone having tested whether not one very long run each week can actually increase.

Cardiff asked lar fitness and you're not doing anything, although have to imagine you probably see some improvement compared to not doing anything, but most people are doing repeated training sessions of cardiff asked strain training. Not a lot of people are doing five days a week of strength training, at least that I wear. Some people are, but most people, I think, are not.

And some people are doing five or more days a week of cardiff. Asked lar training. I'm guessing that most people are not doing five days a week of dedicated static stretch range of motion directed training. But IT does appear that that frequency about the week getting those repeatedly sessions, even if they are short for an individual muscle group, turns out to be important. And so that points to the perhaps the reason why so few people are doing dedicated range of motion work.

But IT also reminds me that all of the studies that were described, at least in this review, and some of the other ones that were not really show impressive changes in limbo ge emotion, I mean twenty plus percent or even fifteen percent with p nf. I think these are big changes that are going to benefit us, that are going to offset the age related losses in flexibility for sure, if one is dedicated about these practices, and in many cases, they are going increased, liberate emotion in ways that are going to allow us Better performance in certain physical endeavors. Certainly, Better baLance are we haven't really talked about baLance and stability, but range of motion can import baLance and stability in some extreme circumstances, but by in large libraries of motion, lack of tightness, improve posture and improve physical performance.

Excuse me, and things of that sort is something that I think we can all benefit from and that are key features of longevity. We don't often think of them because we so pride Ortiz Carter of accused health and the relationship between the heart and brain health and resistance training and moscow skeletal uh hyper phy or strength at SATA. But as I dealt into this leger's ure IT really highlighted for me the extent to which having really good little range of motion, at least maintaining liver range of motion as we age from year to year, and maybe an improving little range of motion, can be immensely beneficial for reducing pain, for, again, improving posture, improving our believe, perform to walk at sea.

And indeed, there's a whole literature that relates our new range of motion to things like pain management of things related to headache and so on and so forth. So liver ange of motion is not just about becoming a contraction ist or are being able to complete the yoga class IT really is about maintaining the integrity and the health of the neural muscular system, the connective tissue and the neural muscular connective network, because those are all indeed working as an ecosystem in a network. I'd like to just briefly touch on p nf stretching for a moment.

Again, this is a vast landscape with many parameters and different practitioners. Lot of, uh, competing opinions out there to put IT lightly. None there's I do want to emphasize that the p nf training leverages those spindle mechanisms and G T, O mechanisms that we talk about earlier.

But I realized that in describing the quarter's ship contraction, hamstring stretch, the mini experiment that hopefully you did that I didn't really highlight the role of the g tos, the golgi tending organs that much. And I just would like just briefly do that for a moment. The gt s have multiple functions. In fact, I think even though gto are in every medical textbook, every physiology textbook, every first year, news scientists learn about them when learning about the neuroscience junctions and the mechanisms of interaction tion. That said, a they're likely to have other functions as well.

And one of the reasons why p nf stretching does work, whether not you're doing that by using a strap to you pull back a limb or whether or not you're actively contracting your quarter steps to then release and emphasize stretching emotion for your hamstrings and related muscle groups, is that activation of those gt s, meaning putting loads and tension into that system, can inhibit the spindles in the opposite in tagish muscle groups. So one of the reasons why lexing, or I should say, contracting your quarter steps really intensely for some bird of time allows your hamstrings to subsequently experiences greater range of motion. And again, it's not just the hamstrings, but the related connective tissue and neural circuits, etta is because, yes, it's and relaxing the hamstrings and the spinal, but there's also a direct relationship between activation of the gt s in the quarter step and release of the spindles in the hamstring and related muscles.

This says the name is called auto gene inhibition, a fancy name for contraction of one muscle group, providing a relaxation of the other muscle group that's tagging tic to IT and IT relates back to this idea of interleaving sets in the gym. So if you think back to that example now, IT should make sense as to why, for instance, if you do, let's say, a set of bench Prices or shoulder Prices, and you let's say you get ten repetitions and you fail on the eleven, that muscle is very, very fatigue. If you were to rest some period of time and then go back and do another set well, during the rest, that muscle group has been relaxing.

It's obviously not contracting in the same way that was during the resistance set. But by going in doing a polling exercise that involves the antagonistic muscle groups are strongly contracting the back muscles through a pool like a pull down or a chin nap or a row type exercise. You're activating or near activating the gt o system in those polling muscles in a way that provides auto gene inhibition for the pushing muscles.

Now again, the physios out there are probably either screaming or banging their heads against whatever a sound system this happens to be arriving through. To them saying wait, but in many cases, the gt s aren't activated enough to provide that other gene inhibition. That's true. But even the sub threshold activation of those interest spinal circuit. So the place where the gt o circuit and the spinal circuit interact can provide an additional replenishment of, say, the pushing muscles while you're activating those polling muscles.

And this is at least one, not the only, but at least one mechanism s by which interleaving pushing poll, pushing poll for both strength and I portrait y training, but also for range of motion stretching type training, can allow you to achieve Better results in a shorter period of time. And I raise this because I want to keep in mind the efficiency of any training program. We just a moment ago, establish that doing, for example, three sets of thirty second static calls can be very useful for the hamstrings, with let to save for sake of simplicity and practicality.

A minutes rest in between. But during that minutes rest, you can stretch the opposite antagonistic muscle group, such as the quarter steps. Or if you want to use p.

Nf training, you could do loading of the quarter steps in between. So there are a number of different ways in which you can start to interleaved static stretching with p nf stretching. You can start to interleaved even p nf type protocols with resistance training.

Although that gets a bit more complicated, you can really start to construct and build protocols that are ideal for you. What we will do is for and upcoming neural network newsletters. So for those of you that aren't familiar, the huberman la poca has a so called neural network news letter.

These are monthly news letters where we put distil points from the podcast and often times protocols in a downloadable pda form. You can access IT by giving us to your email. We don't share your email with anybody.

If you want to see examples of these, you can go to his room and lab, go to the menu and see newsletter. You don't have to sign up for anything to see examples of what these are like. I'll provide a couple of different protocols, one that peer static stretching, one that involves P N F type stretching.

And i'll also put down a protocol that involves the tagish interleaved muscle training of the source that i've been describing a few times throughout this episode. And then you can try and apply those either separately or maybe combine them in some way that's useful for your goals. There are a couple of key elements that are essential for building a safe, effective range of motion increasing program that arrived to us both through the peer reviewed research and admittedly from people.

They're been involved in teaching and training range of motion for a very long period of time. Some of you may be familiar with the so called Anderson method has been around for a long time. I should have never met Anderson.

I don't. I should know this. I don't even know if he's still alive. I hope he's still alive. But in any event, there are a lot of different features to the Anderson and other protocols.

But one of the aspects of the Anderson protocol that I think is highly relevant, in fact I know is relevant to the peer reviewed research that we're going to talk about in a few moments is this notion of pushing through pain and how active or how passive to be about static stretching. Now this is somewhat subjective, right? If you think about getting into a stretch again, we'll just seen the hamstring ings, for example.

So you you either reaching for your toes while seated or maybe you're using a strap in your a raising your foot overhead while lying down or maybe um you you doing a tott type exercise, how far should you reach? Where is the end range of motion? Should you bounce, should you not bounce? We're going to talk a little bit more about that in a moment. But interesting as an interesting idea in principle, which is thread through a lot of his teachings that I think are very much in keeping with the study that i'm about to describe next, where he emphasized to yes, to stretch to the end of the range of motion, but not to focus so much on where that range of motion happens to be that day.

So for instance, not thinking, oh, I can always touch my toes, for instance um and therefore that's the starting place for my flexibility training today but rather to take the entirety of your system into account each day and understand that okay, provided you warmed up appropriately, that you're now going to struct your hamstrings, ks, for instance, and you're going to reach down for your toes, but that your range of motion might be adjust to that day by way of tension and stress or by way of ambient temperature in the room, and to basically define the end range of motion as the place where you can feel the stretch in the relevant muscle groups. I think this is important because unlike resistance training, cardio sclar training, where we can measure distance travel over time, in the case of cardiff asia training, or how much weight is on the bar and count repetitions at a with range of motion training. Of course, range of motion is the feature that we're interested in, but there is likely to be a lot of variation from day to day based on a number of different internal and external factors.

And so the innocent method is really about getting into static and other forms of stretching. I think today, we mainly been focusing on static stretching and holding the end range of motion, but really paying attention to the field of the stretch and the muscles involved. And there are parallels in resistance in cardiff, a training too.

I realized, right in the case of trying to build hypocrisy, or I should say, improve I perty muscle size often times the best advice that one can give us to don't try to lift weights, but rather to chAllenge muscles. Now, of course, you need to provide adequate loads in order to get hyperdrive phy. But when you're training purely for strength, it's about moving weights.

When you're training purely for hypocrisy, or mainly for hypothesis, is really about chAllenging muscles using weights or other forms of resistance, and similarly, and keeping with this Anderson method, when trying to build in range of motion, doing static stretching at a place where it's difficult, but that you can experience the stretch of the muscle cognitive ly, consciously being able to focus on the muscles, and their stretch is at least as useful as is evaluating the current range of motion you're able to achieve. So what does this mean? This means feel the muscles as you stretch them, don't just go through the motions.

And this means don't get so attached to being able to always achieve, for instance, a stretch of a given distance on within a given session. You might actually find that by just finding the place where you can get much further and holding the static stretch there that on the second and third set that you happen to be doing that day, that your range of motion will be increased considerably. Maybe not, but very likely, yes, you will.

And of course, evaluating range of motion over time is the key parameter because that's that's the goal of this type of work. Now along these lines, there is this variable that we ve mention a few times of passive versus active stretching. And there's this even more nebulous variable, this even more kind of subjective thing of how much effort to put into IT should you push into the stretch you even want to bounce a tiny bit, would you want to reach into that end point and trying to extend IT within a given set and session.

And for that reason, I was excited to find this paper um entitled a comparison of two stretching modalities on lower in range of motion measurements in recreational dancers happy to be done in recreational dancers as a six week intervention program that compared low intensity stretching, which they call micro stretching. They use the capital M I don't know if that means that it's propriety, although I didn't see evidence of conflict of interest, but they call IT microbrew ching. But to be very clear, microbrew ching, in the case of this manuscript, is low intensity stretching, and they compared that with moderate intensity static stretching on an active and passive ranges of motion, because there are many different variables are here.

But i'll just highlight out of you that the things that are really most relevant to us and i'll give you the takeaway at the outset and then return to IT at the end so that if I lose any of yours attention in the next couple of minutes, at least you have, uh, that key take away. Basically, what they found was that a six week training program using a very low intensity stretching had a greater positive effect on lower and range of motion. When did moderate intensity static stretching? I find that incredibly interesting.

So very low intensity and will define what that means in a moment here on quoting them. The most interesting aspect to the study was the greater increase in active range emotion compared to passive range emotion by the microstructural group. So this relates what we were just talking about a few moments ago, as IT relates to the Anderson method, which is that very low intensity stretching, meaning effort that feels not painful and in fact, might even feel easy or at least not straining to exceed a given range of motion, turns out to not just be as effective, but more effective than moderate intensity stretching.

So what is low intensity static stretching? Well, they define this as the stretches were completed at an intensity of thirty to forty percent, where one hundred percent equals the point of pain, right? So thirty to forty percent in these individuals, and again, on periphrases, induce a relaxed state within the individual and the specific muscle.

And here they were holding these static stretches, I should mention IT for one minute, not thirty seconds. Now, the control group was doing the exact same overall protocol, so daily, stretching for six weeks, the same exercises, holding each set for sixty seconds. But we're using an intensity of stretch of eighty percent where, again, one hundred represents the point of pain, the point where the person would want to stop stretching.

I find these day incredibly interesting for, I think, what ought to be obvious reasons. If you're going to embark on a flexibility and stretching training program, you don't need to push to the point of pain. In fact, IT seems that even just approaching the point of pain is going to be less effective than Operating at this thirty to forty percent of intensity prior to reaching that pain threshold, the pain thresh being a hundred percent.

Now of course, this is pretty subjective, but I think all of us should be able to register within ourselves. So whether a given range of motion or extending a given range of motion brings us to the threshold of pain or near pain, and according to this study, at least Operating or performing stretching at the intensity that's quite low, that's very relaxing, turns out to be more beneficial in increasing range of motion than is doing. Exercises aimed at increasing range emotion at a higher intensity.

okay. So lower intensity stretching, I should say, Laura, intensity static stretching appears to be the most beneficial way to approach stretching. I think that's a relief um probably to many of us because IT also suggests that the injury risk is going to be lower than if one, we're pushing into the pain zone, so to speak.

The authors offer a number of different explanations as to why this approach, this microstructure ing approach might be more effective. Here i'm perrache from their discussion where they mentioned that they could be hypothesized that they had improved recipe al inhibition within the hamstring muscle groups. So this gets right back to the sorts of neural mechanisms that we talked about before, that somehow by doing this low intensity stretching, that they were able to access some of those spindle and gto type mechanisms that we were referring to earlier.

And the inhibition of hamstring and query p stretches. They also offer a number different um ideas about how this could shift the activation of the so called sympathetic remember the kind of stress division of our nervous system and to reduce that relative to activation of the per sympathetic armor. The nervous system, I can say, have a couple of arguments around sympathetic person, pathetic that are somewhat convoluted.

I will just in fairness to the neuroscience on those systems, I wouldn't suggest putting too much weight on their arguments about sympathetic and paraaortic. To my mind, they didn't really hold much water. But here i'm not trying to be disparate ging of of the overall work, which I think is really quite sound, which is that low intensity so called microstructure ing is going to be the most effective way to increase in range of movement over time.

I wanted just briefly return to this idea, whether not to do ballistic or static stretching before some sort of skill training, or weight training, or any kind of sport, or even Carter of equal exercise like running. Again, the data really split out there. There are even folks who suggest that doing any kind of stretching prior to running is going to lower running efficiency, is going to require essentially more work and more oxygen uptake at a given speed for a variety of reasons.

And runners and that community argue about this endlessly. There are papers in both sides, in both directions. I'm sure i'll hear about some of us in the comments. I'm not really going to take a stance on this as as a consequence because the data all over the place, however, I think there is a general logic that we can apply in here.

I'm borrowing from some conversations and some information put out there by doctor and I galpin, who I think is, of course, both an expert and things about these things in a really sound and flexible way. No one intended. There are instances for, for example, where an individual might want to do some static stretching to increase long range of motion prior to doing weight training, even if it's going to inhibit that person's ability to lift as much weight.

Why would you want to do that? Well, for instance, if somebody has a tightness or a limitation in their neuromuscular connected tissue system, some place in their body, and system that prevents them from using proper form that they can overcome by doing some that stretching well, that would be a great idea, as doctor galban points out. Or for instance, if proper stability within the movement requires increasing in range of motion in some way, well, then compromising the use of greater loads could be greatly offset by doing some statics stretching to improve hamstring flexibility or another muscle group flexibility.

So we can always think about just what's going to allow us or inhibit us from using the maximum amount of weight or from running as far as we want to run, as fast as we want to run. There are insisted where people are trying to overcome injuries, where they're trying to come back from a reparative surgery or something that sort coming back from a layoff where some additional static stretching prior to cardiovascular weight training or skill training or support of some kind is going to be useful because it's going to put us in a position of greater safety and confidence and performance overall, even if it's adJusting down our speed or the total amount of loads that we so it's you that needs to consider whether not for you. And within a given training session, you want to do static training, I should say, static stretching range of motion training prior to or after that training session.

And similarly, there are a lot of data pointing, the fact that doing some dynamic or even ballistic stretching prior to skill training, or cardiff asked lar wait training, can be beneficial in part to warm up the relevant neural circuits, joints and connective tissue and muscles, and as well to perhaps improve range of motion or ability to perform those movements more accurately, with more stability and therefore with more confidence. And while doctor andy galpin would never name any protocol after himself, he's far too humble to do that. I've named a couple of protocols after him, particularly the gallopin equation for hydration, because he was willing to stick his neck out there and put down some specific numbers that people could follow in order to ensure proper hydration during training.

You can look up the group and equation elsewhere. You can just google litter. Look elsewhere, you'll find IT and doctor gelban has also been very thoughtful in generous and I think very accurate in offering a kind of a general organizational logic for how to think about the goals of a particular training session and thereby to decide whether not you're going to do ballistic or static stretching and so on.

And so fourth, so we can refer to this general approach as galen ion, gp ion, that right galpin, ian logic, albania logic. Thus far, we've been talking about stretching for sake of increasing limb flexibility and range of motion, but there are other reasons perhaps to embark on a stretching protocol that include both our ability to relax and access deep relaxation quickly as well as even to reduce inflation tion and perhaps even combat certain forms of cancer. And if that sounds really far fetched, when, to emphasize that the study am about to share with you in a moment, was actually Carried out by one of the directors of a division of the national institutes of health.

And this was the work of healing lang havin, whose a medical doctor has done really important work on the mechanisms underlying things like active puncher, and has approached all that from a very mechanistic viewpoint, right? So not looking just at the effects of occupancy, but really trying to understand what sorts of sidekicks in molecules and pathways are activated, what sorts of neural mechanisms get engaged by things like archibong cure that in pines, on the facial tissues and so forth. And after a length in, is that currently the director of the national institutes of complimentary health and medicine at the national institutes of health.

So this is a major division supported by tax dollars that support systematic mechanistic exploration of things like restrained meditation. 有 个 archibong。 So this is serious science applied to protocols and approaches that have been used for some period of time, but really aimed trying to understand what would the best protocols be to evolve new protocols.

So there's a really interesting study done in animal models, but I think it's a powerful enough result that I think we all should pay attention to. IT the title of this paper. And again, the last author is doctor length in herself is stretching reduces tumor growth in a mouse breast cancer model.

And yes, you can get mice to stretch IT. Turns out that if you gently lift up mice by their tail and they're hold onto their cage there, there's a way in which you can mechanically stretch them in a way that doesn't harm them. First, I should mention that doctor length vin and others have shown that just a brief whole body stretch of that sort induces an increase in activation of the parasympathetic ARM of the economic ervy system.

Again, not ARM lib ARM, but the aspect to the automobile eric system that creates a whole body, whole nervous system shift toward more relaxation. So yes, indeed, stretching induces relaxation at a systemic level, not just at a local level. I think that's important.

Probably not surprising to those of you that use stretching regularly. But yes, IT doesn't need relax us. Yes, you can do this in mice and see that in mice as well.

Here's what they did for this current study. Or he said this was a study, publish twenty eighteen and scientific reports they write. Recent studies have shown that gentle daily stretching for ten minutes can reduce local connective tissue flam tion in fibrosis.

Now that's local tissue inflation tion and fibrosis as well, we now know as systemic, and can induce relaxation systemically. In this case, they focused on mice, not humans, and most were analyze to a stretch versus no stretch condition and were treated for ten minutes once a day for four weeks. So ten minutes of this passive whole body stretching a day for four weeks.

What's remarkable, I mean, just, I have to say, is just striking, is that tumor volume in these mice, they were able to induce tumors in these mice. And the tumor volume at the end point was fifty two percent smaller in the stretch group compared to the no stretch group. This is a highly significant effect, and they point out in the absence of any other treatment.

And they explored whether not set to talk to immune responses, reactivated and a number of other features they weren't able to get too deeply into the underlying mechanisms. But this is pretty remarkable. Even three weeks into the stretching protocol is daily stretching protocol.

For these mice, tumor volume was reduced. I know it's almost having this is pretty incredible. So they have these measures of tumor volume. Uh, and the only difference in the way these animals were were treated and handle that was the introduction of this daily stretch.

I find this result to be, of course, limited in this to the extent that is done in an animal model, not in humans, we have to point IT out. But as they point out in their discussion, our results demonstrate to fifty two percent reduction in memory tumor growth over one month in my undergoing stretching for ten months a day without any other form of therapy. Do they think that stretching itself is changing the tube size? no. In fact, they raise the possibility that stretching, because of its impact on the fashion, might even create microenvironment that are more permissive for tumor growth in certain instances.

So they're careful to emphasize what I also believe to be the case, which is that is unlikely that the stretching itself was directly acting to reduce tumor ze, but rather that there is this possible link between inflation tion and immune exhAusting mechanisms that if you can periodically relax the nervous system here through stretching, that you can affect certain pathways, little to the immune system, that would allow the immune system to combat tumor growth to a significant degree. So again, even though this is a study in mice, IT argues that relaxation induced by stretching can have a powerful influence on memory tumor growth again. Huge effect Carried out by one of the premier labs and individuals who do this sort of work and think about this sort of thing.

And of course, I want to point out IT wasn't just after your lying that did the study there, a number of coauthors and the study, we will provide link to the co authors. Excuse me, we will provide a link to the study so that you can produce IT in more detail, if you like. Now as I related and somewhat final point, i'd like to return this to this idea in this place, this real estate within our brain that we call the insult cortex, the insulation.

To recall, way back at the beginning of this episode, we tried by the van economy neurons that contain vn. Economy, the austrian scientists discovered. And the fact that we are able to make and perform interpretations of our internal landscape pain, our dedication to a practice, for instance, whether not we are in pain because it's a practice that we are doing intentionally and want to improve ourselves or whether not it's pain that's arriving through some externally imposed demands or situation.

Well, the insel is handling all that and fortunately there is a wonderful paper that was published as a few years ago now um in the journal surreal cortex which is a fine journal and this is the year twenty fourteen entitled insular cortex media ates increased pain tolerance in yoga practitioners i'll tell you why, like the study, I am personally not a practice of yoga taking a few yoga classes over the years i've done some of the hot yoga classes. Those rooms can get really, really warm, I confess um and i've done the kind of standard diogo every now and again, it's not something that i've kept up regularly. Um this study explored the effects on brain structure volume in yoga practitioners and for those of you out there that are a noto in yoga, they they pulled subjects from having backgrounds in the here i'm probably going to mispronounce these different things.

And forgive me, the vg, the yoga, Younger yoga, san nana yoga. okay. So some people are new to these practices. Some were experienced that the important takeaway were that they took these yoga practitioners and they didn't explore their brain structure in the context of yoga itself. They looked at things like pain tolerance, so they used thermal stimulation based.

They put people in the conditions where they gave them very hot, very cold stimuli, and compared those yoga practitioners of varying levels of yoga experience to those that had no experience with yoga, so called controls. And they found some really interesting things, are a lot of data, this paper. But here's something i'd like to highlight.

The pain tolerance of yoga practitioners was double or more to that of non yoga practices, even for those that weren't doing this so called hot yoga right. They also found that pain tolerance was significantly greater, both for heat pain and for cold pain. They also found significant increases in insulin, again, the insula, this brain region, gray matter volume. Typically, when we talk about gray matter, we're talking about the so called cell bodies, the the location in neurons, where the genomes house and where the kind of all the housekeeping staff is there. And then White matter volume tends to be the actions, the wires, because they are in sheet with this stuff that appears White m and indeed is White under the micro scope and indeed is White is actually lipid, which is mile.

So increase ed gray matter volume of the insula is a significant finding um because what IT suggest is that people that are doing yoga have an increased volume of these areas of the brain that associated with interaction of awareness and for being able to make judgments about pain and why one is experiencing pain, not just to lean away from pain, but to utilize our leverage, even overcome paignton. So there are many studies of yoga and meditation out there, few that have as much mechanistic detail as this one. And in fact, there's a beautiful figure, figure three, in this paper, that shows that the grain matter of volume of this particular brain region scales in a almost lenie way with the duration of yoga practice that somebody has been taking on in years.

So people that had what they had, a few subjects of up to fifteen or sixteen years of yoga practice had much larger left insular grain matter volume, bigger brain areas associated with these abilities. And I find this interesting because there are a lot of activities out there that don't create these kind of changes in brain volumes, especially within the insula. So IT appears that is not just the performance of the yoga movements, but the overcoming are the kind of pushing into the end ranges, emotion and to push through discomfort to some extent.

Of course, we want people doing that in a, in a healthy, safe way, but that allows yoga practitioners to build up the structure and function of these brain areas that allow them to cope with pain Better than other individuals and to cope with other kinds of interaction. Tive chAllenges, if you will, not just pain but cold, not just pain but discomfort of being in a particular position to do that. And again, we wouldn't want people placing themselves into a compromise position literally, that would harm them, especially given that earlier we heard that microchip ching of the kind of non painful sort, low intensity sort, is actually to be more effective for increasing and range of motion.

But this study really emphasize the extent to which practitioners of yoga don't just learn movements. They learn how to control their nervous system in ways that really shapes their relationship, two pain to flexibility and to the kinds of things that the neural scores system was designed to do. And as a final point, there is a beautiful graph in newspaper.

Beautiful, I think, because IT explorer some of the more subjective dimensions of yoga and insulate function, which is a here i'll read IT out in the nerdy um form and then all explain what IT means. This is a frequency histogram of categories of mental state gies used by yogi's versus controls during the cold pain tolerance task. What describing here and showing is quantitative, timely, how people are conceptualizing cold pain in order to get through IT.

And the different categories are, for instance, distraction, right? Some people just choose to distract themselves from pain or to attempt to other people try to ignore IT. It's a lot like distraction, but none's to engage in a negative emotion sort like like i'm going to dig, i'm going to be resistance to this control.

Subjects tended to use those approaches were as practices of yoga tended to use other sorts of objective approaches, like positive imagery to some extent, the ability to relax despite the extreme cold, the ability to coin court, except like this, is just happening despite the extreme cold, to observe the third person themselves. And the greatest effect, of course, was to breathe, to focus on their aspiration as a way to deal with this chAllenge, this cold chAllenge. Now, all of that is our subjective data, but I want to remind you that the practitioners of yoga are not just using entirely different mental strategies, but they are far more effective at dealing with pain.

Their pain tolerance is much higher as evidence by the other data in the previous crafts in the paper. So well, this podcast episode is most certainly not about yoga persae. It's about flexibility and stretching, flexibility and stretching our elements within yog practices. And of course, yoga practices involve breathing and mental work and a lot of other things. BaLance IT set out a vast landscape, as as many of you know, but I think that if ever there was a manuscript that pointed to the utility of something like yoga, for sake of tapping into a particular set of brain circuits and mechanisms that could wake out into multiple dimensions of life. So day to day life stress, chAllenges in dealing with all sorts of external stressors, career related, family related relationship, actually set to excuse me, but as well for increasing range of motion, for increasing flexibility.

So if ever there was a practice that one could embark on, that would not only increase flexibility in the range of emotion, but would also allow one to cultivate some improved mental functioning, as IT relates to pain tolerance and other features of stress management that no doubt wake out into other years of life, is that yoga is a quite useful practice. And so for those of you that are interested in increasing in range of motion and you're already a practitioner, yoga great can imagine that someday theyll be another study like this one. And you'll be in that, you know ten or fifteen to sixteen year practitioner graph, you'll be that dot way out on the foreign of of the graph that shows that your installation that much bigger than the rest of hours um and therefore your internal awareness and pain thresholds and stress management will be that much Better.

But of course, yoga isn't the only way to increase liver range of motion and flexibility. Up until now, we've described a number of different ways to do that, and we've arrived at some general themes and protocols. Again, those themes and protocols will be distilled into some specific and precise list in our news network newsletter, but we can revisit a couple of them now, just in summary.

And synsi static stretching appears to be at least among the more useful forms of stretching, so low or zero momentum stretching typically, and ranger motion. I love this concept of microbrew ching, even though it's just a couple of studies that have addressed whether high intensity or low intensity static stretch holds are more beneficial. The idea, and indeed the data that low intensity, so thirty to forty percent of of what one would consider painful, appears to be more effective than eighty percent of that threshold, find that incredibly interesting.

And then there's this idea of frequency IT really does appear that getting at least five minutes per week total of stretching for a given muscle group is important for creating meaningful lasting changes in the range of motion. And that is best achieved by five day a week or six day a week or even seven day a week protocols. But those can be very short protocols limited to say three sets of thirty maybe in forty five or sixty seconds of static cold.

Although thirty seconds seems to be a key threshold there um that can get you maximum benefit, there is no need to do full sixty second holds unless you are doing fewer total sessions per week. And of course, to always warm up or to arrive at a stretching session warm. And then of course, there are the other forms of stretching that we touched upon a bit, things like p.

nf. And we talked about why p. Nf works, things like the spinal and the golden attended organ reflexes that are built into all of us that we arrive in this world with. And of course, the other forms of stretching that are known to be effective and important, such as dynamic and ballistic stretching, again, stretching protocols that involve a lot of momentum in order to improve range of motion for performance of particular types of work. That one is about to embark on.

Typically that would be physical work, but a whole interesting and unexplored landscape is the extent to which changing in range of motion and different types of body movement actually shape our cognitive ilium. And that will be the topic of a future epsom of this podcast. If you're learning from and or enjoy in this podcast, please subscribed our youtube channel.

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