Speaker 1: Welcome to Huberman Lab Essentials, where we revisit past episodes
Speaker 1: for the most potent and actionable science based tools for
Speaker 1: mental health, physical health, and performance. I'm Andrew Huberman, and
Speaker 1: I'm a professor of neurobiology and ophthalmology at Stanford School
Speaker 1: of Medicine. Today we are going to discuss the science
Speaker 1: and practice of flexibility and stretching. The important thing that
Speaker 1: I'd like you to know is that flexibility and the
Speaker 1: process of stretching and getting more flexible involves three major components.
Speaker 1: Neural meaning of the nervous system, muscular muscles, and connective tissue.
Speaker 1: Connective tissue is the stuff that surrounds the neural stuff
Speaker 1: and the muscular stuff, although it's all kind of weaved
Speaker 1: together and braded together in complicated ways. So here's a
Speaker 1: key thing that everyone should know, whether or not you're
Speaker 1: talking about flexibility or not. Your nervous system controls your muscles.
Speaker 1: It's what gets your muscles to contract. So within your
Speaker 1: spinal cord, you have a category of neurons nerve cells
Speaker 1: that are called motor neurons. Those neurons release a chemical.
Speaker 1: That chemical is called acetyl coline. The release of acetylcholine
Speaker 1: from these nerve cells these neurons onto the muscles causes
Speaker 1: the muscles to contract. And when muscles contract, they are
Speaker 1: able to move limbs by way of changing the length
Speaker 1: of the muscle, adjusting the function of connective tissue like
Speaker 1: tendons and ligaments. Now, within the muscles themselves, there are
Speaker 1: nerve connections, and these are nerve connections that arise from
Speaker 1: a different set of neurons in the spinal cord that
Speaker 1: we call sensory neurons. These spindle connections within the muscle
Speaker 1: that wrap around the muscle fibers sense the stretch of
Speaker 1: those muscle fibers. So now we have two parts to
Speaker 1: the system that I've described. You've got motor neurons that
Speaker 1: can cause muscles to contract and shorten, and we have
Speaker 1: these spindles within the muscles themselves that wrap around the
Speaker 1: muscle fibers and that information is sent from the muscle
Speaker 1: back to the spinal cord. It's a form of sensing
Speaker 1: what's going on in the muscle. Now, why would that
Speaker 1: be useful? Well, what this does is it creates a
Speaker 1: situation where if a muscle or is stretching too much
Speaker 1: because the range of motion of a limb is increased
Speaker 1: too much, then the muscle will contract to bring that
Speaker 1: limb range of motion into a safe range. Again. Okay,
Speaker 1: so just to clarify, this whole thing looks like a
Speaker 1: loop and the essential components of the loop are motor
Speaker 1: neurons contract muscles. Sensory neurons that we call spindles are
Speaker 1: sensing stretched within the muscles, and if a given muscle
Speaker 1: is elongating because of the increased range of motion of
Speaker 1: a limb, those sensory neurons send an electrical signal into
Speaker 1: the spinal cord such that there is an activation of
Speaker 1: the motor neuron, which by now should make perfect sense
Speaker 1: as to why that's useful. It then short up the muscle.
Speaker 1: It actually doesn't really shorten the muscle, but it contracts
Speaker 1: the muscle that brings the limb back into a safe
Speaker 1: range of motion. So that's one basic mechanism that we
Speaker 1: want to hold in mind, this idea of a spindle
Speaker 1: that senses stretch and can activate contraction of the muscles
Speaker 1: and shorten the muscles. The next mechanism I want to describe,
Speaker 1: and once again there are only two that you need
Speaker 1: to hold in mind. For this episode has to do
Speaker 1: with sensing loads. So at the end of each muscles,
Speaker 1: you have tendons typically, and there are neurons that are
Speaker 1: closely associated with those tendons that are called Golgi tendon organs. Right.
Speaker 1: These are neurons that are sensory neurons that sense how
Speaker 1: much load is on a given muscle. Right, So, if
Speaker 1: you're lifting up something very very heavy, these neurons are
Speaker 1: going to fire, meaning they're going to send electrical activity
Speaker 1: into the spinal cord. And then those neurons have the
Speaker 1: ability to shut down, not activate, but shut down motor
Speaker 1: neurons and to prevent then the contraction of a given muscle. So,
Speaker 1: for instance, if you were to walk over and try
Speaker 1: and pick up a weight that is much too heavy
Speaker 1: for you, meaning you could not do it without injuring yourself.
Speaker 1: There are a number of reasons why you might not
Speaker 1: be able to lift it. But let's say you start
Speaker 1: to get it a little bit off the ground, or
Speaker 1: you start to get some force generator that would allow
Speaker 1: it to move, but the force that you're generating could
Speaker 1: potentially rip your muscles or your tendons off of the bone,
Speaker 1: right that it could disrupt the joints that could tear ligaments. Well,
Speaker 1: you have a safety mechanism in place. It's these Golgi
Speaker 1: tendon organs, these GTOs as they're called, that get activated
Speaker 1: and shut down the motor neurons and make it impossible
Speaker 1: for those muscles to contract. There are also mechanisms that
Speaker 1: arrive to the neuromuscular system from higher up in the
Speaker 1: nervous system, from the brain, and those mechanisms involve a
Speaker 1: couple of different facets that are really interesting and I
Speaker 1: think that we should all know about. In fact, today
Speaker 1: I'm going to teach you about a set of neurons
Speaker 1: that I'm guessing ninety nine point nine percent of you
Speaker 1: have never heard of, including all you neuroscientists out there,
Speaker 1: if you're out there, and I know you're out there,
Speaker 1: that seem uniquely enriched in humans and probably perform essential
Speaker 1: roles in our ability to regulate our physiology and our
Speaker 1: emotional state. So, within the brain, we have the ability
Speaker 1: to send things in the external world something we called xteroception,
Speaker 1: and we have the ability to send things in our
Speaker 1: internal world within our body called interoception. Interception can be
Speaker 1: the volume of food in your gut whether not you're
Speaker 1: experiencing any organ pain or discomfort, whether or not you
Speaker 1: feel good in your gut and in your organs. The
Speaker 1: main brain area that's associated with interpreting what's going on
Speaker 1: in our body is called the insula I nsula. It's
Speaker 1: a very interesting brain region. It's got two major parts.
Speaker 1: The front of it is mainly concerned with things like
Speaker 1: smell and to some extent vision, like if you smell
Speaker 1: something good to approach it, or if you smell something
Speaker 1: bad to avoid it. Posterior insula the back of the insula,
Speaker 1: that is, has a very interesting and distinct set of functions.
Speaker 1: The posterior insula is mainly concerned with what's going on
Speaker 1: with your somatic experience, how do you feel internally? Mainly
Speaker 1: batches information into yum, I want to keep doing this
Speaker 1: or approach this thing, or continue down some path of
Speaker 1: movement or eating or staying in a temperature environment, et cetera.
Speaker 1: Or yuck. I need to get out of here. I
Speaker 1: don't want any more of this. I don't want to
Speaker 1: keep doing this. This is painful or reversive or stressful.
Speaker 1: In your posterior insula, you have a very interesting population
Speaker 1: of very large neurons. These are exceptionally large neurons called
Speaker 1: then economone neurons, neurons that are again unbeknownst to most neuroscientists,
Speaker 1: and they seem uniquely enriched in humans. Why is that interesting, Well,
Speaker 1: these then Economoe neurons have the unique property of interg
Speaker 1: grading our knowledge about our body movements, our sense of
Speaker 1: pain and discomfort, and can drive motivational processes that allow
Speaker 1: us to lean into discomfort and indeed to overcome any
Speaker 1: discomfort if we decide that the discomfort that we are
Speaker 1: experiencing is good for us or directed toward a specific goal.
Speaker 1: And then there's the other really interesting aspect of these
Speaker 1: van Economo neurons, which is that these van Economo neurons
Speaker 1: are connected to a number of different brain areas that
Speaker 1: can shift our internal state from one of so called
Speaker 1: sympathetic activation. So this is a pattern of alertness and
Speaker 1: even stress, sometimes even panic, but typically alertness and stress
Speaker 1: to one so called parasympathetic activation, to one of relaxation.
Speaker 1: Oftentimes you'll hear that stretching should be done by relaxing
Speaker 1: into the stretch. Well, what does it actually mean to
Speaker 1: relax into the stretch? Well, these van Economo neurons sit
Speaker 1: at this juncture where they're able to evaluate what's going
Speaker 1: on inside our body and allow us to access neural
Speaker 1: circuitries by which we can shift our relative level of
Speaker 1: alertness down a bit, or our relative level of stress
Speaker 1: down a bit, and thereby to increase so called parasympathetic
Speaker 1: activation and to literally override some of those spindle mechanisms,
Speaker 1: even the gto mechanisms, but especially the spindle mechanisms at
Speaker 1: the neuromuscular and muscular spinal junction. I'll give you a
Speaker 1: brief example of this that you've already done in your
Speaker 1: life and that we all have the capacity for. What
Speaker 1: I'm referring to is the monosynaptic stretch reflex. This is
Speaker 1: something that every first year neuroscience graduate student learns, which
Speaker 1: is that if you were to step on a sharp
Speaker 1: object with a bare foot, you would not need to
Speaker 1: make the decision to retract your foot. You would automatically
Speaker 1: do that provided you have a healthy nervous system. There
Speaker 1: are mechanisms in place that cause the retraction of that
Speaker 1: limb by way of ensuring that the proper muscles contract
Speaker 1: and other muscles do not contract, in fact, that they
Speaker 1: fully relax. Okay, so in the case of stepping on
Speaker 1: a sharp object like a piece of glass or a
Speaker 1: nail or attack, you would essentially activate the hip flexer
Speaker 1: to lift up your foot as quickly as possible. In
Speaker 1: doing so, that same neural circuit would activate a contraladal,
Speaker 1: meaning opposite side of the body circuit to ensure that
Speaker 1: the leg the foot that's not stepping on the sharp object,
Speaker 1: would do exactly the opposite and would extend to make
Speaker 1: sure that you don't fall over. All of that happens reflexively.
Speaker 1: It does not require any thought or decision making. However,
Speaker 1: if your life depended on walking across some sharp objects,
Speaker 1: let's say, let's make it a little less dramatic, so
Speaker 1: it's not like the Diehard movie or something where you
Speaker 1: have to run barefoot across the glass, although that's a
Speaker 1: pretty good example of what I'm describing here. But let's
Speaker 1: say you had to walk across some very hot stone
Speaker 1: to get away from something that you wanted to avoid.
Speaker 1: You could override that stretch reflex by way of a
Speaker 1: decision made with your upper motor neurons, your insula, and
Speaker 1: your cognition, and almost certainly those van Economoe neurons, which
Speaker 1: would be screaming don't do this, don't do this, don't
Speaker 1: do this, could shuttle that information to brain areas that
Speaker 1: would allow you to override the reflex and essentially push
Speaker 1: through the pain and maybe even in fact, even not
Speaker 1: experience the pain to the same degree or even at all.
Speaker 1: So these van economoeurons sit at a very important junction
Speaker 1: within the brain. They pay attention to what's going on
Speaker 1: in your body pain, pleasure, et cetera, and that includes
Speaker 1: what's going on with your limbs and your limb range
Speaker 1: of motion. They also are paying attention and can control
Speaker 1: the amount of activation, kind of alertness or calmness that
Speaker 1: you are able to create within your body in response
Speaker 1: to a given sensory experience. And as I mentioned before,
Speaker 1: they seem to be uniquely enriched in humans. They seem
Speaker 1: to be related to the aspects of our evolution that
Speaker 1: allow us to make decisions about what to do with
Speaker 1: our body in ways that other animals just simply can't.
Speaker 1: I'd like to take a quick break and acknowledge one
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Speaker 1: there are a number of different types of stretching or
Speaker 1: methods of stretching. Broadly defined, we can describe these as dynamic, ballistic, static,
Speaker 1: and what's called PNF stretching. PNF stands for appropriateceptive neuromuscular facilitation.
Speaker 1: The first two dimension. Dynamic and ballistic stretching both involves
Speaker 1: some degree of momentum and can be distinguished from static
Speaker 1: and PNF type stretching. Now to distinguish dynamic stretching from
Speaker 1: ballistic stretching, like to focus on this element of momentum.
Speaker 1: Both involve moving a limb through a given range of motion.
Speaker 1: In dynamic stretching, however, it tends to be more controlled,
Speaker 1: less use of momentum, especially towards the N range of motion,
Speaker 1: whereas in ballistic stretching there tends to be a bit
Speaker 1: more swinging of the limb or use of momentums. But again,
Speaker 1: dynamic and ballistic stretching both involve movement, so we have
Speaker 1: to generate some force in order to create that movement.
Speaker 1: Ballistic stretching involving a bit more momentum or sometimes a
Speaker 1: lot more momentum, especially at the N range of motion. Now,
Speaker 1: both of those are highly distinct from static stretching, which
Speaker 1: involves holding the N range of motion, so minimizing the
Speaker 1: amount of momentum that's here used. Static stretching can be
Speaker 1: further subdivided into active or passive. Right, there are different
Speaker 1: names for these kinds of approaches. You can hear about
Speaker 1: the Andersen approach or the gender approach. You can look
Speaker 1: these sorts of things up online. There's also passive static stretching,
Speaker 1: in which it's more of a relaxation into a further
Speaker 1: range of motion, and that can be a subtle distinction,
Speaker 1: and nonetheless, static stretching involves both those types of elements
Speaker 1: active and passive, but is really about eliminating momentum. And
Speaker 1: then there's the PNF. The propriate receptive neuromuscular facilitation and
Speaker 1: propriate reception has several different meanings in the context of
Speaker 1: neuroscience and physiology. To just keep it really simple for today,
Speaker 1: propriate reception involves both a knowledge and understanding of where
Speaker 1: our limbs are in space and relative to our body,
Speaker 1: typically relative to the midline. So the brain is often
Speaker 1: trying to figure out where are our limbs relative to
Speaker 1: our midline down the center of our body. And if
Speaker 1: your goal is to increase your hamstring flexibility, the flexibility
Speaker 1: and range of motion of other related muscle systems, you
Speaker 1: might put a strap around your ankle and pull that
Speaker 1: muscle where I should say, excuse me, that limb towards.
Speaker 1: You're not gonna pull the muscle towards. You can pull
Speaker 1: that limb, your ankle towards you try and get it
Speaker 1: sort of back over your head and then progressively relaxing
Speaker 1: into that or maybe even putting some additional force to
Speaker 1: push the end range of motion and then relaxing it
Speaker 1: and then actually trying to stretch that same limb or
Speaker 1: increase the limb range of motion without the strap. There's
Speaker 1: a huge range of PNF protocols. Those protocols can be
Speaker 1: done both by oneself with or without straps, with machines
Speaker 1: with actual weights, or with training partners, so specific exercises
Speaker 1: to target specific muscle groups aside, we've now established that
Speaker 1: there are four major categories of stretching, or at least
Speaker 1: those are the four major categories I'm defining today. But
Speaker 1: in terms of increasing limb range of motion in the
Speaker 1: long term, of truly becoming more flexible as opposed to
Speaker 1: transiently more flexible, static stretching, which includes PNF, appears to
Speaker 1: be the best route to go. So, whether or not
Speaker 1: you want to maintain, re establish, or gain limb range
Speaker 1: of motion, static stretching of holds of thirty seconds appear
Speaker 1: to be best. Now, the question is how long should
Speaker 1: you do that? And how many sets should you do that?
Speaker 1: And how many times a week should you do that?
Speaker 1: To answer those questions, when to turn to what I
Speaker 1: think is a really spectacular review. The title of the
Speaker 1: paper is the relation between stretching typology and stretching duration
Speaker 1: the effects on range of motion. First of all, and
Speaker 1: I quote, all stretching typologies showed range of motion improvements
Speaker 1: over a long term period. However, the static protocols showed
Speaker 1: significant gains with a P value lesson point zero five,
Speaker 1: which means a probability that cannot be explained by chance
Speaker 1: alone when compared to ballistic or PNF protocols. So again,
Speaker 1: what we're hearing is that static stretching is the preferred
Speaker 1: mode for increasing limb range of motion, although here they
Speaker 1: make the additional point that static stretching might even be superior,
Speaker 1: not just to ballistic stretching, but also to PNF protocols.
Speaker 1: The authors go on to say time spent stretching per
Speaker 1: week seems fundamental to illicit range of movement improvements when
Speaker 1: stretches are applied for at least or more than five
Speaker 1: minutes per week. Okay, this is critical. This is not
Speaker 1: five minutes per stretch, remember thirty seconds per static stretch,
Speaker 1: but at least five minutes per week. So what this
Speaker 1: means is that we should probably be doing anywhere from
Speaker 1: two to four sets of thirty second static hold stretches
Speaker 1: five days per week. So what would effective stretching protocol.
Speaker 1: Look like we're all trying to improve limb range of
Speaker 1: motion for different limbs and different muscle groups. Let's talk
Speaker 1: about hamstrings for the time being. This could of course
Speaker 1: be applied to other muscle groups. Let's say you want
Speaker 1: to improve hamstring flexibility and limb range of motion about
Speaker 1: and around the hamstring and involving the hamstring. I want
Speaker 1: to do three sets of static stretching for the hamstring.
Speaker 1: You would do that by holding the stretch for thirty seconds,
Speaker 1: resting some period of time, and doing it again, holding
Speaker 1: for thirty seconds, resting some period of time, and then
Speaker 1: holding it for thirty seconds. That would be one training
Speaker 1: session for the hamstrings. I have to imagine that you'd
Speaker 1: probably want to stretch other muscle groups as well in
Speaker 1: that same session. So three sets of thirty seconds each
Speaker 1: get ninety seconds, and you would do that ideally five
Speaker 1: times a week or maybe even more. One thing that
Speaker 1: did show up in my exploration of the peer reviewed
Speaker 1: research is this notion of warming up for all this.
Speaker 1: We haven't talked about that yet. In general, to avoid injury,
Speaker 1: it's a good idea to raise your core body temperature
Speaker 1: a bit before doing these kinds of stretches, even these
Speaker 1: static stretches, which we can sort of ease into and
Speaker 1: don't involve ballistic movement by definition, and the basic takeaway
Speaker 1: that I was able to find was that if we
Speaker 1: are already warm from running or from weight training, or
Speaker 1: from some other activity, that doing the static stretching practice
Speaker 1: at the end of that weight training or cardiovascular or
Speaker 1: other physical session would allow us to go immediately into
Speaker 1: the stretching session because we're already warm, so to speak. Otherwise,
Speaker 1: raising one's core body temperature by a bit by doing
Speaker 1: five to seven, maybe even ten minutes of easy cardiovascular
Speaker 1: exercise or calistenic movements, provided you can do those without
Speaker 1: getting injured, seems to be an ideal way to warm
Speaker 1: up the body for stretching. We should be warm or
Speaker 1: warm up to stretch, although those warm ups don't have
Speaker 1: to be extremely extensive, And then just by way of logic,
Speaker 1: doing the static stretching after resistance training or cardiovascular training
Speaker 1: seems to be most beneficial in fact, and unfortunately we
Speaker 1: don't have time to go into this in too much
Speaker 1: detail today. I was able to find a number of
Speaker 1: papers that make the argument that static stretching prior to
Speaker 1: cardiovascular training and maybe even prior to resistance training, can
Speaker 1: limit our performance in running and resistance training. I realize
Speaker 1: that's a controversial area. You have those who say no,
Speaker 1: it's immensely beneficial. You have those who say no, it
Speaker 1: inhibits performance, and those that say no, it's a matter
Speaker 1: of how exactly you perform that static stretching and which
Speaker 1: muscle groups and how you're doing this, and how much
Speaker 1: time in between static stretching and performance. But to leave
Speaker 1: all that aside, doing static stretching after some other form
Speaker 1: of exercise, and if not, after some form of exercise,
Speaker 1: after a brief warm up to raise your core body
Speaker 1: temperature definitely seems like the right way to go. I'd
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Speaker 1: not doing five days a week of dedicated statics stretch
Speaker 1: range of motion directed training, but it does appear that
Speaker 1: that frequency about the week getting those repeated sessions, even
Speaker 1: if they are short for an individual muscle group, turns
Speaker 1: out to be important. They're going to offset the age
Speaker 1: related losses in flexibility for sure, if one is dedicated
Speaker 1: about these practices. Some of you may be familiar with
Speaker 1: this so called Anderson method. It's been around for a
Speaker 1: long time. Anderson has an interesting idea in principle which
Speaker 1: has thread through a lot of his teachings that I
Speaker 1: think are very much in keeping with the study that
Speaker 1: I'm about to describe next, where he emphasizes, yes, to
Speaker 1: stretch to the end of the range of motion, but
Speaker 1: not to focus so much on where that range of
Speaker 1: motion happens to be that day. So for instance, not thinking, oh,
Speaker 1: I can always touch my toes, for instance, and therefore
Speaker 1: that's the starting place for my flexibility training today, but
Speaker 1: rather take the entirety of your system into account each
Speaker 1: day and understand that, Okay, provided you're warmed up appropriately,
Speaker 1: that you're now going to stretch your hamstrings, for instance,
Speaker 1: and you're going to reach down for your toes, but
Speaker 1: that your range of motion might be adjusted that day
Speaker 1: by way of tension and stress or by way of
Speaker 1: ambient temperature in the room. And to basically define the
Speaker 1: n range of motion as the place where you can
Speaker 1: feel the stretch in the relevant muscle groups. So what
Speaker 1: does this mean. This means feel the muscles as you
Speaker 1: stretch them, don't just go through the motions. And this
Speaker 1: means don't get so attached to being able to always achieve,
Speaker 1: for instance, a stretch of a given distance on within
Speaker 1: a given session. You might actually find that by just
Speaker 1: finding the place where you can't get much further and
Speaker 1: holding the static stretch there, that on the second and
Speaker 1: third set that you happen to be doing that day,
Speaker 1: that your range of motion will be increased considerably. Now
Speaker 1: along these lines there's this even more nebulous variable, this
Speaker 1: even more kind of subjective thing of how much effort
Speaker 1: to put into it? Should you push into the stretch
Speaker 1: you even want to bounce a tiny bit? Would you
Speaker 1: want to reach into that endpoint and try and extend
Speaker 1: it within a given set and session? And for that
Speaker 1: reason I was excited to find this paper entitled a
Speaker 1: comparison of two stretching modalities on lower limb range of
Speaker 1: motion measurements in recreational dancers. It's a six week intervention
Speaker 1: program that compared low intensity stretching, which they call micro stretching,
Speaker 1: but to be very clear, microstretching in the case of
Speaker 1: this manuscript is low intensity stretching, and they compared that
Speaker 1: with moderate intensity static stretching on an active and passive
Speaker 1: ranges of motion. Basically, what they found was that a
Speaker 1: six week training program using very low intensity stretching had
Speaker 1: a greater positive effect on lower limb range of motion
Speaker 1: then did moderate intensity static stretching. Here I'm quoting them.
Speaker 1: The most interesting aspect of the study was the greater
Speaker 1: increase in active range of motion compared to passive range
Speaker 1: of motion by the microstretching group. So this relates to
Speaker 1: what we were just talking about a few moments ago,
Speaker 1: as it relates to the Anderson method, which is that
Speaker 1: very low intent intensity stretching, meaning effort that feels not
Speaker 1: painful and in fact might even feel easy or at
Speaker 1: least not straining to exceed a given range of motion,
Speaker 1: turns out to not just be as effective, but more
Speaker 1: effective than moderate intensity stretching. So what is low intensity
Speaker 1: static stretching. Well, they define this as the stretches were
Speaker 1: completed at an intensity of thirty to forty percent, where
Speaker 1: one hundred percent equals the point of pain. Right, So
Speaker 1: thirty to forty percent in these individuals, and again I'm paraphrasing,
Speaker 1: induced a relaxed state within the individual and the specific muscle.
Speaker 1: And here they were holding these static stretches. I should
Speaker 1: mention for one minute, not thirty seconds. Now, the control
Speaker 1: group was doing the exact same overall protocol, So daily
Speaker 1: stretching for six weeks, the same exercises, holding each set
Speaker 1: for sixty seconds, but we're using an intensity of stretch
Speaker 1: of eighty percent, where again one hundred represents the point
Speaker 1: of pain to the point where the person would want
Speaker 1: to stop stretching. I find these data incredibly interesting for
Speaker 1: I think what ought to be obvious reasons if you're
Speaker 1: going to embark on a flexibility and stretching training program,
Speaker 1: you don't need to push to the point of pain.
Speaker 1: In fact, it seems that even just approaching the point
Speaker 1: of pain is going to be less effective than operating
Speaker 1: at this thirty to forty percent of intensity Prior to
Speaker 1: reaching that pain threshold, the pain threshold being one hundred percent. Now,
Speaker 1: of course this is pretty subjective, but I think all
Speaker 1: of us should be able to register within ourselves, so
Speaker 1: whether a given range of motion or extending a given
Speaker 1: range of motion brings us to that threshold of pain
Speaker 1: or near pain. And according to this study, at least
Speaker 1: operating or performing stretching at an intensity that's quite low,
Speaker 1: that's very relaxing, turns out to be more beneficial in
Speaker 1: increasing range of motion than is doing exercise is aimed
Speaker 1: at increasing range of motion at a higher intensity. Okay,
Speaker 1: so lower intensity stretching, I should say, lower intensity static
Speaker 1: stretching appears to be the most beneficial way to approach stretching.
Speaker 1: And I think that's a relief, probably to many of us,
Speaker 1: because it also suggests that the injury risk is going
Speaker 1: to be lower than if one were pushing into the
Speaker 1: pain zone, so to speak. I want to just briefly
Speaker 1: return to this idea of whether not to do ballistic
Speaker 1: or static stretching before some sort of skill training or
Speaker 1: weight training, any kind of sport, or even cardiovascular exercise
Speaker 1: like running. There are instances, for example, where an individual
Speaker 1: might want to do some static stretching to increase limb
Speaker 1: range of motion prior to doing weight training. Even if
Speaker 1: it's going to inhibit that person's ability to lift as
Speaker 1: much weight, why would you want to do that. Well,
Speaker 1: for instance, if somebody has a tightness or a limitation
Speaker 1: in their neuromuscular connective tissue system, someplace in their body
Speaker 1: and system that prevents them from using proper form that
Speaker 1: they can overcome by doing some static stretching, well, that
Speaker 1: would be a great idea. There are instances where people
Speaker 1: are trying to overcome injuries, where they're trying to come
Speaker 1: back from a reparative surgery or something of that sort,
Speaker 1: coming back from a layoff, where some additional static stretching
Speaker 1: prior to cardiovascular weight training or skill training or sport
Speaker 1: of some kind is going to be useful because it's
Speaker 1: going to put us in a position of greater safety
Speaker 1: and confidence and performance overall, even if it's adjusting down
Speaker 1: our speed or the total amount of loads that we use.
Speaker 1: And similarly, there are a lot of data points in
Speaker 1: the fact that doing some dynamic or even ballistic stretching
Speaker 1: prior to skill training or cardiovascular weight training can be
Speaker 1: beneficial in part to warm up the relevant neural circuits,
Speaker 1: joints and connective tissue and muscles, and as well to
Speaker 1: perhaps improve range of motion or ability to perform those
Speaker 1: movements more accurately, with more stability and therefore with more confidence.
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Speaker 1: your first ag one subscription. Thus far, we've been talking
Speaker 1: about stretching for sake of increasing limp flexibility and range
Speaker 1: of motion. But there are other reasons perhaps to embark
Speaker 1: on a stretching protocol that include both our ability to
Speaker 1: relax and access deep relaxation. Quickly, I'd like to return
Speaker 1: this to this idea, in this place, this real estate
Speaker 1: within our brain that we call the insular cortex the insula.
Speaker 1: As you recall way back at the beginning of this episode,
Speaker 1: we're talking about the von Economo neurons that Constantine vone
Speaker 1: Economo the Austrian scientists discovered, and the fact that we
Speaker 1: are able to make and perform interpretations of our internal landscape, pain,
Speaker 1: our dedication to a practice, for instance, whether or not
Speaker 1: we are in pain because it's a practice that we
Speaker 1: are doing intentionally and want to improve ourselves, or whether
Speaker 1: or not it's pain that's arriving through some externally imposed
Speaker 1: demands or situations. The insula is handling all that. And
Speaker 1: fortunately there's a wonderful paper that was published was a
Speaker 1: few years ago now in the journal Cerebral Cortex entitled
Speaker 1: Insular Cortex Mediates Increase Pain tolerance in Yoga practitioners. This
Speaker 1: study explored the effects on brain structure volume in yoga practitioners.
Speaker 1: And for those of you out there that are ficinados
Speaker 1: and yoga, they they pulled subjects from having backgrounds in
Speaker 1: the here, I'm probably gonna mispronounce these different things and
Speaker 1: forgive me. The vinyasa yogas, the ashtanga yogas, younger yogas,
Speaker 1: sonanda yogas. Okay. So some people were new to these practices,
Speaker 1: some were experienced that the important takeaways were that they
Speaker 1: took these yoga practitioners and they didn't explore their brain
Speaker 1: structure in the context of yoga itself. They looked at
Speaker 1: things like pain tolerance, so they used thermal stimulation. Basically,
Speaker 1: they put people into conditions where they gave them very
Speaker 1: hot or very cold stimuli, and compared those yoga practitioners
Speaker 1: of varying levels of yoga experience to those that had
Speaker 1: no experience with yoga, so called controls, and they found
Speaker 1: some really interesting things. There a lot of data in
Speaker 1: this paper, but here's something I'd like to highlight. The
Speaker 1: pain tolerance of yoga practitioners was double or more to
Speaker 1: that of non yoga practitioners. They also found significant increases
Speaker 1: in insular again the insula of this brain region gray
Speaker 1: matter volume. Typically, when we talk about gray matter, we're
Speaker 1: talking about the so called cell bodies, the location in
Speaker 1: neurons where the genome is housed and where the kind
Speaker 1: of all the housekeeping stuff is there. And then white
Speaker 1: matter volume tends to be the axons, the wires, because
Speaker 1: they're in sheed with this stuff that appears white in
Speaker 1: MRIs and indeed is white under the microgroscope, and indeed
Speaker 1: is white, it's actually lipid, which is milin. So increased
Speaker 1: gray matter volume of the insula is a significant finding
Speaker 1: because what it suggests is that people that are doing
Speaker 1: yoga have an increased volume of these areas of the brain.
Speaker 1: They're associated with interceptive awareness and for being able to
Speaker 1: make judgments about pain and why one is experiencing pain,
Speaker 1: not just to lean away from pain, but to utilize
Speaker 1: or leverage or even overcome pain. And I find this
Speaker 1: interesting because there are a lot of activities out there
Speaker 1: that don't create these kind of changes in brain volumes,
Speaker 1: especially within the insula. So it appears that it's not
Speaker 1: just the performance of the yoga movements, but the overcoming
Speaker 1: or the kind of pushing into the end ranges of
Speaker 1: motion and to push through discomfort to some extent. Of course,
Speaker 1: we want people doing that in a healthy, safe way,
Speaker 1: but that allows yoga practitioners to build up the structure
Speaker 1: and function of these brain areas that allow them to
Speaker 1: cope with pain better than other individuals and to cope
Speaker 1: with other kinds of inter receptive challenges, if you will,
Speaker 1: not just pain but cold, not just pain but discomfort
Speaker 1: of being in a particular position to do that. And again,
Speaker 1: we wouldn't want people placing themselves into a compromise position
Speaker 1: literally that would harm them, especially given that earlier we
Speaker 1: heard that microstretching of the kind of non painful sort
Speaker 1: low intensity soort is actually going to be more effective
Speaker 1: for increasing end range of motion. But this study really
Speaker 1: emphasized the extent to which practitioners of yoga don't just
Speaker 1: learn movements, they learn how to control their nervous system
Speaker 1: in ways that really reshapes their relationship to pain, to flexibility,
Speaker 1: and to the kinds of things that the neuromuscular system
Speaker 1: was designed to do. So, if ever, there was a
Speaker 1: practice that one could embark on that would not only
Speaker 1: increase flexibility and limb range of motion, but would also
Speaker 1: allow one to cultivate some improved mental functioning as it
Speaker 1: relates to pain tolerance and other features of stress management
Speaker 1: that no doubt wick out into other areas of life.
Speaker 1: Appears that yoga is a quite useful practice. But of
Speaker 1: course yoga isn't the only way to increase limb range
Speaker 1: of motion and flexibility. Up until now, we've described a
Speaker 1: number of different ways to do that, and we've arrived
Speaker 1: at some general themes and protocols. Again, we can revisit
Speaker 1: a couple of them now, just in summary and synthesis,
Speaker 1: static stretching appears to be at least among the more
Speaker 1: useful forms of stretching. It really does appear that getting
Speaker 1: at least five minutes per week total of stretching for
Speaker 1: a given muscle group is important for creating meaningful, lasting
Speaker 1: changes in limb range of motion, and that is best
Speaker 1: achieved by five day a week or six day a
Speaker 1: week or even seven day week protocols. But those can
Speaker 1: be very short protocols, limited to say, three sets of
Speaker 1: thirty maybe even forty five or sixty seconds of static hold,
Speaker 1: although thirty seconds seems to be a key threshold there
Speaker 1: that can get you maximum benefit, and of course to
Speaker 1: always warm up or to arrive at the stretching session warm.
Speaker 1: Thank you once again for joining me today for a
Speaker 1: discussion about the neural and neuromuscular and connective tissue and
Speaker 1: skeletal aspects of flexibility and stretching, and as always, thank
Speaker 1: you for your interest in science.