Improve Flexibility with Research-Supported Stretching Protocols

00:00:00.000 | - Welcome to the Huberman Lab Podcast,

00:00:02.260 | where we discuss science and science-based tools

00:00:04.900 | for everyday life.

00:00:05.920 | I'm Andrew Huberman,

00:00:10.180 | and I'm a professor of neurobiology and ophthalmology

00:00:13.020 | at Stanford School of Medicine.

00:00:14.980 | Today, we are going to discuss the science

00:00:16.820 | and practice of flexibility and stretching.

00:00:19.740 | Flexibility and stretching are topics that I believe

00:00:22.000 | do not receive nearly as much attention as they deserve.

00:00:25.340 | For most people, the topics of flexibility and stretching

00:00:27.680 | bring to mind things like yoga, injury prevention,

00:00:31.080 | or maybe even contortionism.

00:00:33.000 | But it turns out that flexibility and stretching

00:00:35.300 | are features that are built into our basic body plan.

00:00:39.060 | Young children, young animals, and adults,

00:00:42.240 | and indeed older children and animals,

00:00:44.840 | all stretch and all have some degree of flexibility.

00:00:48.640 | It turns out that having flexibility

00:00:50.460 | and our ability to stretch,

00:00:52.120 | and the interaction between stretching and flexibility,

00:00:55.140 | are fundamental to how we move,

00:00:57.700 | our ability to learn new movements,

00:00:59.940 | indeed also to prevent injury or repair injuries,

00:01:04.140 | and to offsetting and reducing inflammation

00:01:07.080 | throughout the body.

00:01:07.920 | In fact, today I'm going to share with you

00:01:09.500 | a remarkable set of studies that show

00:01:11.580 | that stretching can actually adjust things

00:01:13.940 | like tumor growth.

00:01:15.580 | This is work that was done by one of the major directors

00:01:17.720 | of the National Institutes of Health.

00:01:19.620 | So today's discussion will start with a description

00:01:22.060 | of the mechanisms, literally the cells

00:01:24.860 | and the connections from your nervous system

00:01:26.620 | that mediate flexibility and stretching.

00:01:28.920 | And I promise that I'll make that information

00:01:30.620 | accessible to you,

00:01:31.940 | whether or not you have a biology background or not.

00:01:34.820 | Then with that information in hand,

00:01:36.660 | I'm going to present to you

00:01:37.600 | what the scientific literature says

00:01:39.100 | about the best times and ways to stretch.

00:01:41.980 | Everything right down to the detail

00:01:43.260 | of how long to hold a stretch,

00:01:45.180 | whether or not to hold a stretch at all,

00:01:46.600 | because it turns out there are multiple kinds of stretching.

00:01:49.180 | So you can imagine you have stretches

00:01:50.380 | where you hold the stretch for a very long time

00:01:53.060 | and use as little momentum as possible.

00:01:55.140 | And then there's also what's called

00:01:56.460 | dynamic and ballistic stretching,

00:01:57.920 | where you're literally swinging your limbs,

00:01:59.740 | trying to increase the range of motion.

00:02:01.660 | I will explain the science and application of flexibility

00:02:04.120 | and stretching in the context of sports performance,

00:02:07.300 | whether or not you're engaging in cardiovascular exercise

00:02:09.900 | or resistance exercise or both,

00:02:12.420 | whether or not you're a competitive athlete

00:02:13.920 | or simply a recreational exerciser, as I am,

00:02:17.360 | whether or not you are trying to increase

00:02:19.580 | your range of motion and flexibility for longevity purposes,

00:02:22.520 | or whether or not you're trying to do it

00:02:24.040 | in order to access different parts of your nervous system,

00:02:26.700 | 'cause we'll soon learn today

00:02:28.360 | that your ability to improve flexibility

00:02:31.480 | and the need to engage in specific stretching exercises

00:02:34.960 | can actually be used to powerfully modulate your ability

00:02:37.780 | to tolerate pain, both emotional and physical pain.

00:02:41.320 | So this thing that we call flexibility and stretching

00:02:44.000 | is actually a vast landscape.

00:02:45.760 | We're going to simplify and organize all that for you today.

00:02:48.400 | And by the end of today's episode,

00:02:50.080 | you're going to have a number of simple,

00:02:51.960 | easy-to-apply tools that are grounded

00:02:53.860 | in the best scientific research

00:02:55.440 | that you can apply for your specific goals.

00:02:58.040 | Before we begin, I'd like to emphasize

00:02:59.840 | that this podcast is separate from my teaching

00:03:01.840 | and research roles at Stanford.

00:03:03.740 | It is, however, part of my desire and effort

00:03:05.900 | to bring zero cost to consumer information

00:03:07.840 | about science and science-related tools

00:03:10.140 | to the general public.

00:03:11.620 | In keeping with that theme,

00:03:12.680 | I'd like to thank the sponsors of today's podcast.

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00:07:22.680 | Let's talk about flexibility and stretching.

00:07:25.480 | Before we talk about the practices

00:07:27.240 | of flexibility and stretching,

00:07:29.100 | I'd like to just highlight some of the features

00:07:30.800 | that are already built into your nervous system

00:07:33.040 | and into your body that allow you to be flexible.

00:07:36.560 | Some of us feel tighter than others,

00:07:38.880 | sometimes in specific limbs or areas of our body.

00:07:41.960 | Some people feel really loose and limber.

00:07:44.400 | Some people even have what's called a hyper flexibility.

00:07:47.740 | I, for instance, have a relative that can take her fingers

00:07:50.380 | and bend them back to the point where they touch her wrist.

00:07:53.400 | And it always makes me cringe a little bit,

00:07:56.060 | but she can do that without any pain.

00:07:57.460 | She seems to have some hyper flexibility in her joints.

00:07:59.520 | I do not have that feature.

00:08:01.280 | Some of you may find that you are more flexible

00:08:03.120 | than others naturally.

00:08:04.480 | And some of you might be thinking,

00:08:06.440 | you don't need to build in additional flexibility.

00:08:08.920 | Well, I think by the end of today's episode,

00:08:11.640 | you'll realize that almost all of us can benefit

00:08:14.240 | from having some sort of understanding about flexibility

00:08:17.240 | and having some stretching protocol

00:08:19.380 | that we incorporate into our life,

00:08:21.400 | if not just for physical performance reasons

00:08:24.520 | and for postural reasons,

00:08:26.020 | then also for cognitive and mental reasons.

00:08:29.560 | And I'll be sure to clarify what all of that means.

00:08:32.080 | Right now, I'd like to take a moment

00:08:34.240 | and just highlight the flexibility that you already have.

00:08:37.380 | For instance, if you were to move your arm

00:08:40.420 | behind your torso a little bit and then sort of let go

00:08:44.320 | or stop exerting any effort in doing that,

00:08:47.560 | you would find that the limb would return more or less

00:08:49.960 | to a position next to your torso, at least I would hope so.

00:08:53.300 | Now, why is that?

00:08:54.440 | Well, it turns out that there are aspects

00:08:56.020 | of your nervous system, aspects of your skeletal system,

00:09:00.160 | aspects of your muscles and aspects of the connective tissue

00:09:04.120 | that binds all of that together,

00:09:06.680 | that try and restore a particular order or position

00:09:10.520 | to your limbs and your limbs relative to one another.

00:09:14.260 | So that reflects a very specific set of processes

00:09:17.540 | that it turns out are the same set of processes

00:09:20.080 | that you use when you are trying

00:09:21.400 | to enhance flexibility and stretching.

00:09:24.120 | So I'd like to just take a moment

00:09:25.800 | and review the basic elements of nervous system, muscle,

00:09:30.860 | connective tissue, and skeletal tissue, bone,

00:09:34.620 | that allow for flexibility and stretching.

00:09:38.020 | And here we can point to two major mechanisms

00:09:40.840 | by which your nervous system, neurons, meaning nerve cells,

00:09:44.520 | communicate with muscles,

00:09:46.500 | and those muscles communicate back to your nervous system

00:09:50.200 | to make sure that your limbs don't stretch too far,

00:09:52.840 | they don't move too far such that you get injured.

00:09:56.500 | And in addition to that,

00:09:58.680 | mechanisms that ensure that you don't overload your muscles

00:10:01.800 | too much with weight or with tension or with effort

00:10:05.040 | and damage them that way.

00:10:06.660 | Because it turns out that the second security mechanism

00:10:09.800 | of making sure that you don't overload muscles

00:10:11.920 | can be leveraged toward increasing your flexibility

00:10:14.960 | almost immediately.

00:10:16.640 | That's right, there are protocols and tools

00:10:18.700 | that I'll share with you that are going to allow you

00:10:20.420 | to vastly improve your flexibility over time,

00:10:24.960 | but there are also mechanisms that allow you

00:10:26.740 | to quite significantly increase your degree of flexibility

00:10:30.880 | in a very short period of time, within just a few seconds.

00:10:34.380 | So let's establish some of the basic biological mechanisms.

00:10:38.400 | In time we talk about biology or physiology,

00:10:40.920 | we're going to talk about structure,

00:10:42.520 | meaning the cells and their connections,

00:10:44.200 | and functions, what they do.

00:10:46.300 | They're just a few names to understand,

00:10:47.900 | you do not have to memorize these names.

00:10:50.240 | The important thing that I'd like you to know

00:10:52.080 | is that flexibility and the process of stretching

00:10:54.560 | and getting more flexible involves three major components,

00:10:58.780 | neural, meaning of the nervous system,

00:11:01.180 | muscular, muscles, and connective tissue.

00:11:04.280 | Connective tissue is the stuff that surrounds

00:11:06.860 | the neural stuff and the muscular stuff,

00:11:09.420 | although it's all kind of weaved together

00:11:11.080 | and braided together in complicated ways.

00:11:13.340 | Some of you may have heard of fascia,

00:11:14.980 | we're going to talk a little bit about fascia today,

00:11:16.720 | although it's such an interesting tissue

00:11:18.980 | that's really deserving of its own episode.

00:11:21.860 | Facial tissue, we're going to talk about

00:11:23.980 | some of the stuff that surrounds muscles

00:11:25.920 | that really gives you your shape

00:11:27.380 | and holds everything together

00:11:28.680 | and allows for flexibility to occur.

00:11:31.440 | So here's a key thing that everyone should know,

00:11:33.700 | whether or not you're talking about flexibility or not.

00:11:37.120 | Your nervous system controls your muscles,

00:11:40.200 | it's what gets your muscles to contract.

00:11:42.740 | So within your spinal cord,

00:11:44.280 | you have a category of neurons, nerve cells,

00:11:46.900 | that are called motor neurons.

00:11:48.940 | To be precise, they are lower motor neurons

00:11:51.160 | 'cause they're in your spinal cord.

00:11:53.480 | We call them lower to distinguish them

00:11:55.040 | from the motor neurons that are in your brain

00:11:57.680 | up in your skull.

00:11:58.880 | Those lower motor neurons,

00:12:01.940 | hereafter, I'll just refer to them as motor neurons.

00:12:04.820 | If I want to talk about the other kind of motor neurons,

00:12:06.660 | I'll say upper motor neurons.

00:12:07.700 | So if I say motor neurons,

00:12:08.760 | I just mean the ones in your spinal cord.

00:12:10.860 | Those motor neurons send a little wire

00:12:14.220 | or set of wires out to your muscles,

00:12:17.020 | and that creates what's called a neuromuscular junction,

00:12:20.380 | which just means that the neurons meet the muscles

00:12:22.340 | at a particular place.

00:12:23.880 | Those neurons release a chemical.

00:12:25.880 | That chemical is called acetylcholine.

00:12:28.860 | Some of you may have heard about acetylcholine before.

00:12:31.080 | Acetylcholine also exists in your brain

00:12:33.620 | and does other things in your brain,

00:12:35.100 | mainly it's involved in focus and attention,

00:12:38.160 | but at the neuromuscular junction,

00:12:40.180 | the release of acetylcholine from these nerve cells,

00:12:43.140 | these neurons onto the muscles,

00:12:44.980 | causes the muscles to contract.

00:12:46.820 | And when muscles contract,

00:12:48.380 | they are able to move limbs by way of changing the length

00:12:53.380 | of the muscle, adjusting the function of connective tissue,

00:12:59.060 | like tendons and ligaments.

00:13:00.580 | And for instance,

00:13:01.640 | if you're bringing your wrist closer to your shoulder,

00:13:04.020 | that biceps muscle is contracting, it's getting shorter.

00:13:08.180 | I mean, in reality, it hasn't gotten shorter overall.

00:13:10.660 | It's just temporarily shorter, of course.

00:13:13.140 | All of that is controlled by neurons.

00:13:15.920 | And it's those motor neurons from the spinal cord

00:13:18.720 | that are really responsible for the major movement

00:13:21.720 | of your limbs by way of causing contraction

00:13:25.460 | of specific muscles at specific times.

00:13:27.620 | So the key thing to take away

00:13:28.980 | is that nerve controls the contraction of muscles.

00:13:33.360 | Now, within the muscles themselves,

00:13:36.420 | there are nerve connections.

00:13:39.300 | And these are nerve connections that arise

00:13:41.400 | from a different set of neurons in the spinal cord

00:13:43.500 | that we call sensory neurons.

00:13:45.740 | The sensory neurons exist in a different part

00:13:48.340 | of the spinal cord, and they send a little wire

00:13:50.960 | or set of wires into the muscles.

00:13:53.060 | And there's a particular kind of sensory neuron

00:13:55.840 | that comes out of your spinal cord and into your muscles,

00:13:58.420 | which are called spindle neurons.

00:14:01.860 | They create, or they actually wrap around muscle fibers,

00:14:06.380 | kind of corkscrew around them.

00:14:08.020 | They give kind of a spring-like appearance.

00:14:10.120 | If for you aficionados out there,

00:14:12.140 | these are intrafusal connections or neurons,

00:14:15.780 | intrafusal means within the muscle,

00:14:18.040 | but you really don't need to know that

00:14:19.820 | unless you're really curious about it,

00:14:21.740 | or you're going to become a neuroscientist,

00:14:23.060 | or you're in medical school or something.

00:14:25.340 | These spindle connections within the muscle

00:14:29.820 | that wrap around the muscle fibers

00:14:31.580 | sense the stretch of those muscle fibers.

00:14:35.780 | So now we have two parts to the system that I've described.

00:14:39.260 | You've got motor neurons that can cause muscles to contract

00:14:42.100 | and shorten, and we have these spindles

00:14:46.040 | within the muscles themselves

00:14:48.180 | that wrap around the muscle fibers,

00:14:50.240 | and that information is sent from the muscle

00:14:53.180 | back to the spinal cord.

00:14:55.140 | It's a form of sensing what's going on in the muscle,

00:14:58.740 | much in the same way that you have neurons in your eye

00:15:01.100 | that sense light in your external environment.

00:15:03.940 | You have neurons in your ear that sense sound waves

00:15:06.860 | in your external environment.

00:15:08.300 | You have neurons in your spinal cord

00:15:10.720 | that are sensory neurons that are sensing

00:15:12.780 | the amount of stretch in the muscles.

00:15:16.540 | What happens is if a given muscle is stretching really far,

00:15:21.080 | those sensory neurons, those spindles within the muscle

00:15:24.860 | will activate and will send a electrical potential,

00:15:28.820 | literally a bit of electricity along that wire's length

00:15:31.780 | into the spinal cord, and then within the spinal cord,

00:15:35.140 | that sensory neuron communicates

00:15:37.480 | through a series of intermediate steps,

00:15:39.120 | but to the motor neuron

00:15:42.180 | and make sure that that motor neuron contracts.

00:15:45.180 | Now, why would that be useful?

00:15:46.680 | Well, what this does is it creates a situation

00:15:49.220 | where if a muscle is stretching too much

00:15:52.580 | because the range of motion of a limb is increased too much,

00:15:56.760 | then the muscle will contract to bring that limb range

00:16:00.120 | of motion into a safe range again.

00:16:03.740 | Now, what determines whether or not a range of motion

00:16:06.140 | is "safe" or not is dictated by a number of things.

00:16:10.120 | It's dictated by things that are happening

00:16:11.720 | in this kind of loop of neural connections

00:16:13.720 | in the spinal cord and muscle.

00:16:15.160 | It's also determined by what's going on in your head,

00:16:18.400 | literally in your mind, cognitively,

00:16:20.120 | about whether or not the movement of that limb,

00:16:22.640 | its increasing range of motion is good for you,

00:16:25.420 | whether or not you're doing it deliberately,

00:16:27.120 | whether or not it's bad for you,

00:16:28.140 | and then there are also some basic safety mechanisms

00:16:31.360 | that are put in there that really try

00:16:33.200 | and restrict our limb range of motion.

00:16:35.800 | Okay, so just to clarify,

00:16:37.580 | this whole thing looks like a loop,

00:16:39.040 | and the essential components of the loop are

00:16:41.280 | motor neurons contract muscles,

00:16:43.520 | sensory neurons,

00:16:46.300 | of which there are a bunch of different varieties,

00:16:47.860 | in this case, what we're calling the spindles,

00:16:49.560 | are sensing stretch within the muscles,

00:16:51.600 | and if a given muscle is elongating

00:16:55.080 | because of the increased range of motion of a limb,

00:16:58.760 | those sensory neurons send an electrical signal

00:17:01.080 | into the spinal cord such that there is an activation

00:17:04.580 | of the motor neuron, which by now should make perfect sense

00:17:07.680 | as to why that's useful.

00:17:08.680 | It then shortens up the muscle.

00:17:10.680 | It actually doesn't really shorten the muscle,

00:17:11.960 | but contracts the muscle that brings the limb back

00:17:14.280 | into a safe range of motion, okay?

00:17:17.580 | So this process is very fast.

00:17:21.460 | It was designed to keep your body together and safe.

00:17:25.920 | It's designed to make sure that you don't, you know,

00:17:27.960 | take your arm and swing it behind your torso,

00:17:29.820 | and it just goes all the way back

00:17:30.940 | to the middle of your back.

00:17:31.840 | I mean, unless you're a contortionist,

00:17:33.100 | or you've trained that kind of level of flexibility,

00:17:35.560 | that would be terrible because it could provide

00:17:37.060 | a lot of damage to the muscles

00:17:39.960 | and to the connective tissue and so forth.

00:17:42.880 | So that's one basic mechanism that we want to hold in mind,

00:17:46.400 | this idea of a spindle that senses stretch

00:17:48.520 | and can activate contraction of the muscles

00:17:50.480 | and shorten the muscles.

00:17:51.760 | The next mechanism I want to describe,

00:17:53.640 | and once again, there are only two

00:17:55.360 | that you need to hold in mind for this episode,

00:17:58.320 | this other mechanism has a lot of the same features

00:18:01.000 | as the one I just described,

00:18:02.640 | but it has less to do with stretch.

00:18:04.780 | In fact, it doesn't have to do with stretch

00:18:06.180 | as much as it has to do with sensing loads.

00:18:09.720 | So at the end of each muscles, you have tendons typically,

00:18:14.520 | and there are neurons that are closely associated

00:18:19.520 | with those tendons that are called Golgi tendon organs.

00:18:23.660 | These are neurons that are sensory neurons

00:18:26.400 | that sense how much load is on a given muscle.

00:18:29.480 | So if you're lifting up something very, very heavy,

00:18:31.920 | these neurons are going to fire,

00:18:33.700 | meaning they're going to send electrical activity

00:18:35.280 | into the spinal cord.

00:18:36.640 | And then those neurons have the ability to shut down,

00:18:41.120 | not activate, but shut down motor neurons

00:18:44.280 | and to prevent the contraction of a given muscle.

00:18:47.800 | So for instance, if you were to walk over

00:18:49.720 | and try and pick up a weight that is much too heavy for you,

00:18:53.880 | meaning you could not do it without injuring yourself

00:18:56.440 | and you start to try and heave that weight off the ground,

00:19:00.440 | there are a number of reasons why you might not be able

00:19:02.160 | to lift it, but let's say you start

00:19:03.400 | to get it a little bit off the ground,

00:19:04.940 | or you start to get some force generated

00:19:08.360 | that would allow it to move.

00:19:10.260 | But the force that you're generating could potentially

00:19:13.480 | rip your muscles or your tendons off of the bone, right?

00:19:16.920 | That it could disrupt the joints and it could tear ligaments.

00:19:20.000 | Well, you have a safety mechanism in place.

00:19:21.720 | It's these Golgi tendon organs, these GTOs as they're called

00:19:25.240 | that get activated and shut down the motor neurons

00:19:27.600 | and make it impossible for those muscles to contract, okay?

00:19:31.040 | So on the one hand, we have a mechanism that senses stretch

00:19:33.720 | and can figure out when stretch is excessive.

00:19:36.800 | And when the system detects that stretch is excessive,

00:19:40.420 | it activates the contraction of muscles.

00:19:43.340 | And then we have a second mechanism that senses loads.

00:19:47.520 | And when tension or loads is deemed excessive

00:19:51.140 | by these circuits, and remember,

00:19:52.460 | these circuits don't have a mind.

00:19:53.440 | They don't go, oh, this is excessive.

00:19:55.000 | They just sense loads.

00:19:56.200 | And when those loads exceed a certain threshold,

00:19:58.620 | well, then those GTOs, those Golgi tendon organs

00:20:01.960 | send signals into the spinal cord that shut down

00:20:04.820 | your motor neurons' ability to contract muscles

00:20:07.280 | so that you no longer can lift that heavy load.

00:20:09.720 | So both of these are protective mechanisms,

00:20:12.220 | but both of these can be leveraged in a very logical way

00:20:16.160 | and in a very safe way in order to increase

00:20:18.500 | your limb range of motion.

00:20:20.200 | So there are a couple of things I want to point out

00:20:22.000 | before going a little bit further

00:20:24.040 | into how your nervous system controls

00:20:26.520 | flexibility and stretching.

00:20:28.240 | And those key points are the following.

00:20:30.960 | There are now dozens, if not hundreds of studies

00:20:34.200 | that show that a dedicated stretching practice

00:20:38.840 | can improve limb range of motion.

00:20:41.200 | Now, for many of you listening, you're probably saying duh,

00:20:43.960 | but I think it's important to point that out,

00:20:46.280 | that a dedicated stretching practice

00:20:48.200 | can increase limb range of motion.

00:20:50.560 | And as you'll soon learn, there are specific mechanisms

00:20:53.440 | that can explain that effect.

00:20:55.120 | The second point is one of longevity.

00:20:57.600 | And when I say longevity, I don't necessarily mean

00:21:00.520 | late stage aging.

00:21:02.300 | We all undergo a decrease in limb range of motion

00:21:06.220 | unless we do something to offset that decrease.

00:21:09.120 | And the current numbers vary from study to study,

00:21:11.740 | but if you look en masse, you look at all of those studies,

00:21:14.580 | and what you basically find is that we start to experience

00:21:18.480 | a decrease in flexibility from about age 20

00:21:21.660 | until about age 49, that's pretty dramatic.

00:21:24.520 | And then of course it will continue after age 49,

00:21:27.660 | but basically it's a 10% decrease every 10 years.

00:21:30.960 | So we could say it's a 1% decrease per year,

00:21:33.720 | although it's not necessarily linear.

00:21:35.520 | What do I mean by that?

00:21:36.360 | Well, it's not necessarily that on your 21st birthday,

00:21:39.620 | you are 1% less flexible than you were

00:21:42.100 | on your 20th birthday and it decreased by 1% per year.

00:21:45.240 | Some of these changes can be non-linear.

00:21:47.160 | So you can imagine the person who's doing just fine

00:21:49.020 | in terms of flexibility between 20 and 30,

00:21:51.820 | and then, you know, they get to 32

00:21:53.920 | and suddenly they've lost 5% of their flexibility.

00:21:56.220 | Now, of course, there will be a ton of lifestyle factors

00:21:58.760 | if you're a regular practitioner of yoga,

00:22:00.560 | if you have a dedicated stretching practice,

00:22:02.340 | if you're doing other things to improve

00:22:04.360 | your muscle contractibility,

00:22:06.120 | so you're doing resistance training, it turns out,

00:22:07.960 | can actually indirectly improve flexibility.

00:22:11.720 | There are a number of different factors,

00:22:13.360 | but the key point is that maintaining some degree

00:22:16.360 | of flexibility and maybe even enhancing range of motion

00:22:20.020 | and flexibility is of immense benefit

00:22:22.660 | for offsetting injury provided it's not pushed too far.

00:22:26.700 | There are a number of people who have pushed

00:22:28.660 | their limb range of motion so far

00:22:31.300 | that they experience all sorts of injuries,

00:22:33.820 | both acute and chronic injuries.

00:22:35.500 | Today, we'll also talk about how to avoid those scenarios.

00:22:38.420 | Okay, so we've established that there are mechanisms

00:22:40.160 | within the spinal cord, muscles, and connective tissue.

00:22:42.740 | Those, remember, it's the motor neurons, the spindles,

00:22:45.800 | the GTOs, and of course, the muscles themselves,

00:22:49.360 | and connective tissue, tendons,

00:22:51.760 | but also other forms of connective tissue

00:22:54.180 | that establish whether or not a limb is going to stay

00:22:57.920 | within a particular range of motion or not,

00:22:59.900 | and whether or not a limb is going to be allowed

00:23:03.180 | by the nervous system to pursue or handle a given load,

00:23:07.800 | a given tension.

00:23:08.840 | There are also mechanisms that arrive

00:23:12.500 | to the neuromuscular system from higher up

00:23:15.820 | in the nervous system, from the brain,

00:23:18.120 | and those mechanisms involve a couple of different facets

00:23:21.060 | that are really interesting,

00:23:23.120 | and I think that we should all know about.

00:23:24.960 | In fact, today, I'm going to teach you about a set

00:23:26.680 | of neurons that I'm guessing 99.9% of you have never heard

00:23:30.480 | of, including all you neuroscientists out there,

00:23:32.920 | if you're out there, and I know you're out there,

00:23:36.420 | that seem uniquely enriched in humans

00:23:40.540 | and probably perform essential roles

00:23:43.260 | in our ability to regulate our physiology

00:23:45.440 | and our emotional state.

00:23:47.040 | So within the brain, we have the ability to sense things

00:23:50.320 | in the external world, something we call exteroception,

00:23:53.320 | and we have the ability to sense things

00:23:55.040 | in our internal world, within our body,

00:23:57.120 | called interoception.

00:23:58.540 | Interoception can be the volume of food in your gut,

00:24:01.340 | whether or not you're experiencing any organ pain

00:24:03.400 | or discomfort, whether or not you feel good in your gut

00:24:05.760 | and in your organs.

00:24:06.600 | That's actually kind of feeling, I feel great,

00:24:08.800 | I feel sated, I feel relaxed,

00:24:10.920 | but those are all different forms of interoception.

00:24:13.980 | The main brain area that's associated

00:24:16.440 | with interpreting what's going on in our body

00:24:18.520 | is called the insula, I-N-S-U-L-A.

00:24:21.220 | It's a very interesting brain region.

00:24:22.780 | It's got two major parts.

00:24:24.140 | The front of it is mainly concerned with things like smell

00:24:29.140 | and to some extent, vision, and to some extent,

00:24:33.160 | other things that are arriving from the external world

00:24:36.180 | and combining with what's going on internally

00:24:39.000 | and making sense of all that,

00:24:41.120 | or at least routing that information

00:24:42.720 | elsewhere in your nervous system to make decision,

00:24:44.700 | like if you smell something good to approach it,

00:24:46.460 | or if you smell something bad to avoid it.

00:24:48.240 | The front of the insula is really doing

00:24:50.220 | all of that kind of stuff, along with other brain areas.

00:24:53.720 | The posterior insula, the back of the insula, that is,

00:24:57.820 | has a very interesting and distinct set of functions.

00:25:01.760 | The posterior insula is mainly concerned

00:25:04.380 | with what's going on with your somatic experience.

00:25:07.960 | How do you feel internally and how is the movement

00:25:12.560 | that you happen to be doing,

00:25:13.960 | combining with your internal state to allow you to feel,

00:25:19.120 | as I like to say, the nervous system

00:25:20.920 | mainly batches things into yum,

00:25:23.120 | like, oh, this is really good for me.

00:25:25.040 | Yuck, this is really bad for me and I need to stop,

00:25:27.600 | or meh, this is kind of neutral.

00:25:29.720 | Okay, so this isn't about food,

00:25:31.280 | but we could say for most stimuli,

00:25:33.400 | most senses, whether or not they're senses of things

00:25:35.780 | internally or externally,

00:25:37.540 | our nervous system is trying to make decisions

00:25:39.360 | about what to do with that information.

00:25:40.780 | And so it mainly batches information into yum,

00:25:43.340 | I want to keep doing this or approach this thing,

00:25:46.060 | or continue down some path of movement or eating

00:25:50.480 | or staying in a temperature environment, et cetera,

00:25:53.560 | or yuck, I need to get out of here,

00:25:55.220 | I don't want any more of this,

00:25:56.360 | I don't want to keep doing this,

00:25:57.400 | this is painful or aversive or stressful, and then meh.

00:26:01.160 | So if it doesn't really matter,

00:26:02.140 | I can just kind of stay right here or not.

00:26:03.740 | Yum, yuck, and meh.

00:26:05.420 | Well, in your posterior insula,

00:26:09.040 | you have a very interesting population

00:26:11.960 | of very large neurons,

00:26:13.500 | these are exceptionally large neurons,

00:26:16.000 | called van economone neurons.

00:26:18.700 | These are neurons that are, again,

00:26:21.140 | unbeknownst to most neuroscientists

00:26:22.940 | and they seem uniquely enriched in humans.

00:26:26.380 | Chimpanzees have them

00:26:28.060 | and some other large animals have them.

00:26:30.220 | So they're found in whales, chimpanzees, elephants,

00:26:34.260 | and in humans.

00:26:35.580 | But even though we are much smaller than most whales,

00:26:38.660 | and even though we are much smaller than most elephants,

00:26:41.560 | I mean, remember there are baby elephants,

00:26:43.480 | as far as I know, they haven't bred up mini elephants yet,

00:26:47.060 | they seem to have a teacup version

00:26:49.100 | of pretty much every dog breed.

00:26:50.940 | You can look that up,

00:26:53.260 | I certainly have mixed feelings

00:26:55.060 | about this notion of trying to downsize everything

00:26:57.540 | to the point where you could kind of like

00:26:58.900 | the pocket-sized bulldog I think someday will arrive.

00:27:01.360 | I'm not a fan of that kind of downsizing

00:27:03.180 | of different breeds.

00:27:04.540 | But because there aren't teacup elephants

00:27:06.420 | and teacup gorillas and teacup chimpanzees and so forth,

00:27:10.260 | most all of those other species are larger than us.

00:27:13.100 | They have these van economone neurons

00:27:15.900 | and we have these van economone neurons,

00:27:18.020 | but we have in upwards of 80,000 of these things

00:27:22.420 | in our posterior insula.

00:27:24.020 | These other species tend to have

00:27:25.560 | somewhere in the range of 1,000 to maybe 10,000 or so.

00:27:29.200 | Why is that interesting?

00:27:30.760 | Well, these van economone neurons

00:27:33.960 | have the unique property of integrating

00:27:36.900 | our knowledge about our body movements,

00:27:40.780 | our sense of pain and discomfort,

00:27:43.240 | and can drive motivational processes

00:27:45.660 | that allow us to lean into discomfort

00:27:48.000 | and indeed to overcome any discomfort

00:27:50.440 | if we decide that the discomfort that we are experiencing

00:27:53.080 | is good for us or directed toward a specific goal.

00:27:57.020 | This knowledge turns out to be very important

00:27:58.780 | to keep in mind because as we migrate this conversation

00:28:01.880 | toward the things that we can do

00:28:03.340 | to enhance flexibility in stretching,

00:28:05.380 | you'll soon learn that there are moments

00:28:08.480 | within a stretching protocol where you have the opportunity

00:28:11.880 | to either override pain and discomfort,

00:28:14.540 | to kind of relax through it or push through it.

00:28:18.100 | There's a decision fork in the road there,

00:28:21.180 | and I'll tell you which fork in the road to take

00:28:23.860 | or to say, uh-uh, I'm not going to do that.

00:28:26.700 | I'm going to allow these natural reflexes of the spindle

00:28:29.300 | to kick in and just essentially stop me from stretching

00:28:32.460 | if a given limb isn't designed

00:28:34.620 | or shouldn't be stretched that far.

00:28:37.380 | So I'd like you to keep these van economone neurons in mind.

00:28:41.180 | I should mention they're named van economone

00:28:44.220 | because the guy, Constantine van economone,

00:28:46.340 | that discovered them at the end of the 1800s, early 1900s,

00:28:51.180 | decided to name them after himself as many scientists do,

00:28:54.060 | or certainly the neurologists and physicians

00:28:56.820 | are famous for naming things after themselves.

00:28:58.860 | These van economone neurons turn out to be very important

00:29:01.740 | to keep in mind as we embark on our exploration

00:29:04.740 | of what sorts of stretching practices

00:29:08.100 | can be best applied to increase flexibility

00:29:11.500 | because whether or not you undertake a mild, moderate

00:29:16.300 | or intense flexibility training,

00:29:19.540 | you will no doubt encounter a scenario at some point

00:29:23.500 | where you will have to ask yourself,

00:29:26.100 | do I quote unquote relax into this stretch

00:29:29.340 | or do I try and push through

00:29:31.220 | just a little bit of discomfort?

00:29:33.020 | And I'll explain how to gauge that decision

00:29:35.420 | in a very specific and ideally safe way.

00:29:38.900 | And I'll give you some tools

00:29:39.740 | that will allow you to make that decision

00:29:41.060 | in the way that best preserves the integrity

00:29:43.560 | of those neural circuits that I described earlier

00:29:45.780 | and can keep you safe.

00:29:47.560 | These van economone neurons sit in the exact position

00:29:51.760 | that one would want to be able to evaluate

00:29:54.180 | what's going on in the body,

00:29:55.840 | in particular, what's going on in terms of limb movements,

00:29:58.360 | how that relates to our feelings of discomfort.

00:30:00.680 | And then there's the other aspect

00:30:03.580 | of these van economone neurons,

00:30:04.960 | which is that these van economone neurons

00:30:07.800 | are connected to a number of different brain areas

00:30:10.800 | that can shift our internal state

00:30:12.760 | from one of so-called sympathetic activation.

00:30:15.160 | So this is a pattern of alertness and even stress,

00:30:19.540 | sometimes even panic, but typically alertness and stress

00:30:23.040 | to one of so-called parasympathetic activation

00:30:25.860 | to one of relaxation.

00:30:28.800 | Oftentimes you'll hear that stretching should be done

00:30:32.740 | by relaxing into the stretch.

00:30:34.860 | Well, what does it actually mean to relax into the stretch?

00:30:37.660 | Well, these van economone neurons sit at this junction

00:30:40.960 | where they're able to evaluate

00:30:42.300 | what's going on inside our body

00:30:44.440 | and allow us to access neural circuitries

00:30:47.000 | by which we can shift our relative level of alertness

00:30:50.920 | down a bit or our relative level of stress down a bit

00:30:55.240 | and thereby to increase so-called parasympathetic activation

00:30:59.520 | and to literally override some of those spindle mechanisms,

00:31:04.380 | even the GTO mechanisms,

00:31:05.860 | but especially the spindle mechanisms

00:31:08.340 | at the neuromuscular and musculospinal junction.

00:31:12.880 | And in that way, gently, subtly override the reflex

00:31:17.880 | that would otherwise cause us to contract those muscles back.

00:31:20.960 | The reason that's possible is because your brain

00:31:25.340 | has those other kinds of motor neurons,

00:31:27.000 | the upper motor neurons that can both direct,

00:31:30.720 | meaning control, and can override lower motor neurons.

00:31:34.940 | I'll give you a brief example of this

00:31:37.320 | that you've already done in your life

00:31:39.000 | and that we all have the capacity for.

00:31:41.600 | What I'm referring to is the monosynaptic stretch reflex.

00:31:45.600 | This is something that every first year

00:31:48.200 | neuroscience graduate student learns,

00:31:50.000 | which is that if you were to step on a sharp object

00:31:53.040 | with a bare foot, you would not need to make the decision

00:31:56.740 | to retract your foot.

00:31:58.080 | You would automatically do that

00:31:59.960 | provided you have a healthy nervous system.

00:32:02.140 | There are mechanisms in place

00:32:03.840 | that cause the retraction of that limb

00:32:06.660 | by way of ensuring that the proper muscles contract

00:32:10.560 | and other muscles do not contract.

00:32:13.040 | In fact, that they fully relax, okay?

00:32:14.800 | So in the case of stepping on a sharp object,

00:32:17.360 | like a piece of glass or a nail or a tack,

00:32:19.800 | you would essentially activate the hip flexor

00:32:22.080 | to lift up your foot as quickly as possible.

00:32:25.500 | In doing so, that same neural circuit would activate

00:32:30.500 | a contralateral, meaning opposite side of the body circuit

00:32:34.960 | to ensure that the leg, the foot,

00:32:37.120 | that's not stepping on the sharp object

00:32:39.160 | would do exactly the opposite and would extend

00:32:41.760 | to make sure that you don't fall over.

00:32:44.600 | All of that happens reflexively.

00:32:46.520 | It does not require any thought or decision-making.

00:32:50.240 | In fact, humans without any neocortex,

00:32:54.580 | literally they're who are decerebrate

00:32:56.560 | or an animal that doesn't have, and when I say decerebrate,

00:33:00.500 | I mean lack of cerebral cortex,

00:33:02.480 | they can perform that because it's all controlled

00:33:06.460 | by circuits that are basically below the brain

00:33:09.420 | and in the spinal cord.

00:33:11.300 | There's a little bit of activation of circuits

00:33:12.780 | in the kind of deeper parts of the brain,

00:33:14.460 | but basically you don't need to think or decide

00:33:16.900 | in order to do that.

00:33:18.180 | However, if your life depended on walking across

00:33:22.940 | some sharp objects, let's say,

00:33:25.060 | let's make it a little less dramatic

00:33:26.380 | so it's not like the "Die Hard" movie or something

00:33:28.220 | where he has to run barefoot across the glass,

00:33:30.860 | although that's a pretty good example

00:33:32.620 | of what I'm describing here,

00:33:34.060 | but let's say you had to walk across some very hot stones

00:33:37.420 | to get away from something that you wanted to avoid.

00:33:40.860 | You could override that stretch reflex

00:33:43.880 | by way of a decision made with your upper motor neurons,

00:33:46.460 | your insula, and your cognition,

00:33:47.860 | and almost certainly those van econimo neurons,

00:33:50.080 | which would be screaming, "Don't do this, don't do this,

00:33:51.860 | "don't do this," could shuttle that information

00:33:53.860 | to brain areas that would allow you to override the reflex

00:33:57.460 | and essentially push through the pain and maybe even,

00:34:00.620 | in fact, even, not experience the pain to the same degree

00:34:04.780 | or even at all.

00:34:06.440 | So these van econimo neurons sit at a very important junction

00:34:10.260 | within the brain.

00:34:11.280 | They pay attention to what's going on in your body,

00:34:14.520 | pain, pleasure, et cetera,

00:34:17.580 | and that includes what's going on with your limbs

00:34:19.480 | and your limb range of motion.

00:34:21.200 | They also are paying attention

00:34:23.540 | and can control the amount of activation,

00:34:27.120 | kind of alertness or calmness

00:34:28.580 | that you are able to create within your body

00:34:32.460 | in response to a given sensory experience.

00:34:35.520 | And as I mentioned before,

00:34:37.340 | they seem to be uniquely enriched in humans.

00:34:39.460 | They seem to be related to the aspects of our evolution

00:34:43.880 | that allow us to make decisions

00:34:46.140 | about what to do with our body

00:34:47.820 | in ways that other animals just simply can't.

00:34:50.560 | Before we go any further,

00:34:51.540 | I want to give you a practical tool

00:34:53.420 | that you can, of course, use,

00:34:55.300 | but that will also give you insight and experience

00:34:58.840 | into your muscle spindle spinal cord circuit mechanisms.

00:35:03.380 | So what I'd like you to do

00:35:05.500 | is if you're in a proper place to do this,

00:35:07.860 | you're going to stand with legs straight,

00:35:10.260 | meaning knees not bent,

00:35:11.740 | and you're going to try and touch your toes,

00:35:13.860 | or for some of you, that's going to be very easy

00:35:16.260 | and you might even be able to put your hands

00:35:18.100 | flat on the floor.

00:35:20.060 | I don't have that kind of flexibility.

00:35:21.220 | It's pretty easy for me to touch my toes.

00:35:23.160 | I don't care if you round your back or not,

00:35:24.900 | although ideally I would say don't round your back,

00:35:27.740 | not because it's bad to do so necessarily,

00:35:29.760 | but just to try and keep this the same

00:35:32.740 | from trial to trial, as it were.

00:35:34.860 | So try and get a sense of what your range of motion is

00:35:37.980 | in terms of bending over at the waist

00:35:40.580 | while maintaining a flat back

00:35:41.860 | and trying to touch your toes or even touch the floor.

00:35:43.960 | Maybe again, you can even go hands flat to the floor,

00:35:46.700 | maybe even far out in front of you.

00:35:48.780 | Okay, now what I'd like you to do is stand back up,

00:35:52.260 | and I'd like you to contract your quadriceps

00:35:56.780 | as hard as you possibly can for about five to 15 seconds,

00:36:01.260 | let's say 10 seconds,

00:36:02.300 | just to keep things more or less normalized.

00:36:04.880 | This obviously is not a super controlled experiment.

00:36:08.140 | So to contract your quadriceps,

00:36:09.540 | for those of you that don't know,

00:36:10.420 | you're going to extend your lower limb out.

00:36:13.320 | So this would be like kicking,

00:36:14.620 | although don't do it too quickly.

00:36:15.740 | You're going to kick out your foot.

00:36:18.920 | You should feel your quadriceps contract

00:36:20.760 | on the top of your thighs,

00:36:22.020 | and you're going to try and consciously

00:36:24.200 | contract them as hard as you can, okay?

00:36:26.520 | Typically, if you want to point your toe

00:36:28.940 | back towards your knee or shin,

00:36:30.380 | that's also going to help somewhat

00:36:32.160 | to contract even harder and harder, okay?

00:36:35.100 | So do that for about 10 seconds.

00:36:36.880 | A lot of you will do this just while standing,

00:36:40.020 | contract, contract, contract, okay, then release it.

00:36:42.620 | And then now go ahead and repeat that stretch

00:36:47.140 | where you're trying to touch your toes or touch the floor.

00:36:49.460 | So this is, again, relying more or less on hamstring

00:36:52.300 | flexibility among other things, okay?

00:36:54.820 | What most of you will find is that you have

00:36:57.700 | an immediate increase in hamstring flexibility

00:37:01.060 | or your range of motion has increased.

00:37:04.300 | If you didn't experience that,

00:37:05.560 | then I would encourage you to try and contract

00:37:07.580 | your quadriceps harder and longer,

00:37:09.380 | so maybe 20 or 30 seconds,

00:37:11.060 | and then try this so-called experiment again.

00:37:13.760 | Why would contracting your quadriceps

00:37:17.300 | allow your hamstring flexibility to suddenly increase?

00:37:21.840 | Well, the way that our muscles are organized

00:37:25.140 | is such that we have muscles that are antagonistic

00:37:28.860 | to one another.

00:37:29.980 | So our quadriceps and our hamstrings work

00:37:33.640 | in sort of a push-pull fashion, if you will.

00:37:36.680 | They can antagonize one another.

00:37:38.500 | So when you move your heel towards your glutes,

00:37:42.160 | you are using your hamstring.

00:37:43.700 | The hamstring obviously also does other things

00:37:45.540 | related to hip movement.

00:37:46.860 | And when you lift your knee or when you extend your foot

00:37:51.860 | and contract your quadriceps,

00:37:54.960 | you are essentially relaxing the hamstrings.

00:37:58.300 | Now, of course, most movements involve

00:37:59.860 | both quadricep and hamstring in synchrony,

00:38:02.740 | and that synchrony is really an elegant one,

00:38:04.900 | but here we're more or less isolating the quadriceps

00:38:07.060 | from the hamstrings, at least to the extent

00:38:08.900 | that it can leverage these spindle stretch mechanisms.

00:38:12.120 | So what happens is when you contract your quadriceps hard,

00:38:15.500 | you are relaxing or releasing some of the stretch

00:38:20.500 | that's occurring in those intrafusal spindle sensory fibers

00:38:24.420 | going into your spinal cord.

00:38:25.820 | And as a consequence, you're able then

00:38:29.660 | to stretch your hamstrings further,

00:38:33.420 | or we can be more accurate and say that your range of motion

00:38:37.300 | about the hamstring and its related joints is greater

00:38:40.980 | when you aren't engaging that spindle reflex,

00:38:43.980 | which would cause the hamstrings to contract, okay?

00:38:46.580 | So if you are somebody who has tight hamstrings,

00:38:48.740 | there could be a variety of reasons for that,

00:38:50.980 | but part of the reason is likely to be neural,

00:38:54.580 | and you can release that neural spindle reflex

00:38:57.580 | by contracting the opposite antagonistic muscle,

00:39:01.460 | which in this case is the quadriceps.

00:39:03.260 | The same thing is true and can be leveraged

00:39:05.660 | for stretching other muscles.

00:39:07.020 | So for instance, if you're going to do a tricep stretch,

00:39:08.780 | the typical kind of overhead where you grab your elbow

00:39:10.980 | and move it toward the midline of your body

00:39:13.620 | with the other hand, using your opposite hand,

00:39:16.360 | well, you can do that.

00:39:17.680 | And then I would suggest trying to flex your bicep,

00:39:21.060 | contract your bicep, that is, while doing that.

00:39:23.700 | And for most people, you'll notice a increase

00:39:26.560 | in the tricep range of motion or ability

00:39:29.140 | to kind of lean into or to relax into

00:39:32.800 | or to push that stretch a little bit further.

00:39:36.780 | Now, for you physios out there,

00:39:38.900 | and for those of you that have backgrounds in kinesiology,

00:39:42.000 | I want to acknowledge, of course,

00:39:43.160 | there are other mechanisms that are coming into play.

00:39:45.720 | There are actually neural connections

00:39:47.820 | within the joints themselves

00:39:49.280 | that are providing proprioceptive feedback,

00:39:51.120 | et cetera, et cetera.

00:39:52.120 | But this is simply to illustrate

00:39:54.320 | that part of our range of motion is determined

00:39:58.280 | by these spindle mechanisms

00:39:59.900 | that I spent some time focusing on earlier.

00:40:03.020 | And indeed, this approach can be leveraged

00:40:05.800 | toward creating increased limb range of motion,

00:40:09.340 | not just for the hamstrings, but for your quadriceps.

00:40:11.960 | So for instance, if you have tight quadriceps,

00:40:14.620 | you can do the opposite.

00:40:15.680 | You can contract your hamstring very intensely

00:40:19.600 | for let's say 10 seconds or 20 seconds or 30 seconds.

00:40:23.040 | So that would take some conscious effort

00:40:24.560 | of bringing your heel up towards your glutes.

00:40:28.520 | You could do that in a way

00:40:29.540 | that you're really trying to contract those muscles hard.

00:40:31.600 | You'd have to use some deliberate hamstring activation there,

00:40:34.160 | meaning you have to use those upper motor neurons

00:40:36.280 | and the other aspects of your upper brain power, as it were,

00:40:39.960 | to try and really contract your hamstrings

00:40:42.800 | as intensely as possible.

00:40:44.720 | Then you would relax that,

00:40:46.480 | and then you would do your quadricep stretch again.

00:40:49.000 | And if you did a pre-hamstring contraction measurement

00:40:52.140 | of your quadricep flexibility,

00:40:54.640 | and then you did a post-hamstring contraction measure

00:40:58.400 | of your quadricep flexibility,

00:41:00.880 | almost certainly you would find

00:41:01.880 | that that flexibility had increased.

00:41:03.880 | Now, of course, the muscle really didn't change much.

00:41:06.880 | The tendons didn't change much.

00:41:08.560 | What changed was the patterns of neural activation

00:41:10.900 | that were restricting you from, in the first case,

00:41:13.880 | stretching your hamstring or having a,

00:41:16.760 | to be more accurate, we should say,

00:41:18.120 | to having a certain range of motion about the hamstring

00:41:22.120 | and its related joints.

00:41:23.340 | And those break mechanisms were removed.

00:41:26.780 | And of course, then when you contract your hamstring,

00:41:28.520 | you're removing some of the neural breaks,

00:41:30.400 | the spindle acting as a break

00:41:33.400 | and inhibiting that quadricep range of motion.

00:41:37.200 | Okay, so you can imagine this.

00:41:38.980 | And in fact, you can apply this

00:41:40.020 | for any number of different muscles.

00:41:41.760 | The larger muscles and the sort of biceps, triceps,

00:41:44.600 | and hamstrings, quadriceps are sort of the simplest place

00:41:48.600 | to think about this and to apply it.

00:41:50.340 | But in theory, and indeed in practice,

00:41:52.980 | it really works for all the various muscle groups.

00:41:55.740 | It's just sometimes harder to access

00:41:57.320 | these so-called antagonistic muscle groups.

00:42:00.160 | Now, we should take a moment and just discuss

00:42:04.080 | what actually happens as we get more flexible

00:42:06.440 | in the short term and long term.

00:42:07.520 | I just mentioned what happens in the short term.

00:42:09.620 | Clearly, those don't involve lengthening of the muscles.

00:42:13.920 | It's not like the muscles slide along the bones

00:42:16.020 | or that the tendons really stretch out that much more

00:42:19.160 | than they had prior to that kind of exercise.

00:42:22.880 | But it is the case that if people stretch consistently

00:42:27.880 | over a given period of several weeks or more,

00:42:30.740 | that there are changes in the muscles.

00:42:33.320 | This gets a little bit tricky in terms of nomenclature.

00:42:35.600 | And I just want to highlight that

00:42:36.960 | because I think that a number of people

00:42:39.440 | get frustrated and confused, in fact,

00:42:43.160 | when we talk about muscles getting longer.

00:42:46.360 | You know, the whole concept of a muscle getting longer

00:42:48.820 | isn't really in keeping with reality,

00:42:50.760 | but there are elements within the muscles

00:42:53.220 | that can change their conformation.

00:42:55.480 | So to get a little bit detailed here,

00:42:57.300 | and we won't spend too much time on this,

00:42:58.600 | but I just want to acknowledge this

00:42:59.760 | for those of you that are interested

00:43:00.720 | in neuromuscular physiology

00:43:02.040 | and how it relates to flexibility.

00:43:03.960 | You know, you have your muscle fibers

00:43:05.840 | and then you have your so-called myofibrils.

00:43:08.600 | So you can imagine kind of a single fiber.

00:43:12.060 | That fiber, of course,

00:43:12.900 | will get input from those motor neurons.

00:43:14.920 | And then within those fibers,

00:43:17.360 | you have what are called sarcomeres.

00:43:18.840 | And you can kind of think about sarcomeres

00:43:20.320 | as little segments, kind of like the segments of bamboo.

00:43:22.560 | If you ever look at bamboo, it's not just one big stalk.

00:43:25.340 | It's got those little out pouchings along the way

00:43:28.520 | that kind of break up what would be just one big stalk

00:43:34.080 | of bamboo into different segments, but they're all connected.

00:43:37.080 | The sarcomeres are somewhat like that.

00:43:40.520 | And within the sarcomeres,

00:43:41.960 | you have a couple of different components.

00:43:43.440 | One thing is called myosin, which is like a thick layer,

00:43:46.800 | and then the other is actin.

00:43:48.160 | And those are interdigitated, as we say.

00:43:50.920 | They're kind of connected to one another,

00:43:52.380 | kind of like if you were to put your fingers together

00:43:54.160 | from your two hands,

00:43:55.740 | if you were going to put your fingers in between one another,

00:43:58.160 | that's interdigitate, literally interdigitated in this case.

00:44:01.040 | So pun intended.

00:44:02.980 | And the myosin and actin kind of move relative

00:44:07.940 | to one another, and they have a lot to do

00:44:09.500 | with your ability to contract muscles.

00:44:11.600 | When we stretch muscles,

00:44:14.540 | when we go through a stretching practice,

00:44:16.420 | there are a number of things that change, some neural,

00:44:19.160 | some related directly to connective tissue,

00:44:21.540 | but also it appears from really nice work,

00:44:23.680 | mainly done from McGill University.

00:44:26.060 | I'll provide a link to a couple of these studies

00:44:27.540 | if you want to dig in there more deeply,

00:44:30.140 | that change the conformation, the relative size and spacing

00:44:34.840 | of some of these things like sarcomeres

00:44:36.660 | and the way that myosin and actin kind of work together.

00:44:40.380 | But we don't want to think of muscles as lengthening.

00:44:44.360 | We can, however, think about the resting state of a muscle

00:44:48.460 | being slightly different or indeed very different

00:44:51.540 | than the resting state of a muscle of somebody

00:44:54.800 | or of a limb that has not undergone

00:44:57.020 | regular flexibility training.

00:44:58.620 | So that's as much time as I want to spend on that

00:45:00.480 | because we could spend an entire hour

00:45:01.860 | getting right down into the details.

00:45:03.820 | But I do want to emphasize, however,

00:45:05.500 | that muscles have different parts, they have fibers,

00:45:07.860 | they have sarcomeres, they have myosin, they have actin.

00:45:11.520 | But the idea of making our muscles longer,

00:45:13.860 | that reflects a number of processes that occur

00:45:16.380 | basically within an existing muscle length.

00:45:19.860 | The length of our muscle bellies

00:45:21.720 | and where our insertions are relative

00:45:24.900 | to our connective tissue in our limbs

00:45:26.620 | is genetically determined, right?

00:45:29.500 | Some people have, for instance,

00:45:30.820 | a bicep that goes all the way from the crook of their elbow

00:45:34.020 | up to their shoulder, right?

00:45:36.340 | And some people can, you know,

00:45:38.180 | if they were to put their arm at a 90 degree angle,

00:45:40.500 | could put two or three fingers

00:45:41.880 | between their bicep and their elbow.

00:45:44.300 | They have a, we can say, a shorter bicep, relatively shorter.

00:45:48.340 | Now, the reason I mention

00:45:49.540 | these highly detailed cellular mechanisms

00:45:52.080 | is because as we start to embark on different protocols

00:45:56.300 | for using stretching to increase flexibility

00:45:59.460 | and range of motion,

00:46:00.940 | we need to ask ourselves

00:46:02.580 | what is preventing our ability to extend range of motion?

00:46:06.660 | Is it the spindle, right?

00:46:08.060 | Is it because the muscle is stretching too much?

00:46:10.880 | Oftentimes it can be because of that

00:46:12.460 | and or because of a sense of pain

00:46:14.540 | or simply a sense that the muscle is not in a position

00:46:18.820 | that it's been in before

00:46:20.220 | that's unrelated to pain or to spindle activation.

00:46:23.340 | And oftentimes it can be related directly

00:46:27.260 | to these changes in the confirmation of myosin and actin

00:46:31.300 | and within the context of the sarcomeres.

00:46:34.080 | Now, of course you can't peer into

00:46:35.820 | or sense your individual sarcomeres.

00:46:37.960 | However, you do have neurons that innervate these areas

00:46:41.660 | and that send that sensory information

00:46:43.400 | back into the spinal cord

00:46:44.420 | and up to your brain to interpret.

00:46:45.980 | So you'll find that as we move along,

00:46:48.220 | there are specific adjustments that you can make

00:46:50.900 | at both the macro level,

00:46:52.740 | meaning how much movement to insert into your stretching,

00:46:56.660 | right, is it going to be a static or dynamic

00:46:58.300 | or even a ballistic stretch?

00:47:00.040 | Or for instance, at the micro level

00:47:03.220 | that even just a slight sub millimeter or millimeter increase

00:47:08.060 | in the stretching of a given muscle and related tissues

00:47:12.700 | can translate into an increased range of motion performance.

00:47:16.140 | As a quick but relevant aside,

00:47:17.500 | I thought I'd share with you something useful

00:47:19.620 | that's also grounded in this notion of antagonistic muscles.

00:47:24.240 | So for those of you that do resistance training,

00:47:26.880 | whether or not it's with body weight

00:47:28.180 | or with physical weights or machines, what have you,

00:47:31.620 | you may have found that if you,

00:47:32.940 | let's say were to do three sets of a pushing exercise.

00:47:35.740 | So this could be pushups, this could be bench presses,

00:47:38.900 | this could be shoulder presses, something of that sort.

00:47:41.760 | And then later in the workout, you were to do,

00:47:45.060 | let's say machine pull downs or pull ups

00:47:48.080 | or chin ups of some sort.

00:47:49.140 | So a pulling exercise.

00:47:51.220 | Typically what you would find is if you were to do

00:47:53.300 | what's often called straight sets,

00:47:55.420 | so you would do three sets of pushups,

00:47:57.500 | let's say with two minutes of rest in between,

00:48:00.580 | that you might be able to get a certain number of

00:48:02.260 | repetitions on the first set.

00:48:04.320 | Just for sake of example,

00:48:05.800 | let's say you can get 10 repetitions on the first set,

00:48:09.100 | and then you get eight repetitions on the second set,

00:48:12.700 | and then you get six repetitions on the third set

00:48:14.660 | with two minutes in between.

00:48:16.460 | And then you would move on at some point to your

00:48:19.220 | pulling exercises.

00:48:20.620 | And similarly, let's say you were doing chin ups

00:48:22.900 | or pull downs, and you would get 10 repetitions,

00:48:25.220 | rest two minutes, eight repetitions,

00:48:26.940 | rest two minutes and six repetitions.

00:48:28.780 | Okay, fine.

00:48:30.060 | Well, typically what people discover is that

00:48:33.700 | if they interleave their pushing and pulling exercises,

00:48:37.100 | provided they do that for muscles that are antagonistic

00:48:39.900 | to one another.

00:48:40.860 | So in this case, pushing with the chest,

00:48:43.860 | shoulders and triceps for the pushing exercises and pulling

00:48:46.780 | with the back and biceps,

00:48:48.460 | and of course there are other muscles involved as well.

00:48:50.580 | But because those muscle groups are at least in part

00:48:52.900 | antagonistic to one another,

00:48:54.780 | what people often find is that if they were to say,

00:48:57.480 | do their pushing set, get 10 repetitions,

00:49:00.700 | then move to a pulling set after just say 60 seconds

00:49:05.700 | and perform that pulling set,

00:49:09.280 | then go back to the pushing set,

00:49:13.020 | then go back to a pulling set, push, pull, push, pull.

00:49:16.140 | In other words, interleaving their sets,

00:49:18.040 | even if they were to maintain the same amount of rest

00:49:21.500 | between sets of pushing and sets of pulling,

00:49:24.380 | what they discover often is that the drop in the number of

00:49:30.120 | repetitions that they get is somewhat offset.

00:49:32.360 | So rather than get 10, eight, six,

00:49:34.820 | as it were with the straight sets,

00:49:36.460 | it will be 10, nine, eight.

00:49:39.860 | So what this means is not that you're increasing

00:49:43.740 | the total rest time to four minutes between sets,

00:49:45.940 | because then of course it wouldn't be equivalent,

00:49:48.800 | but rather that while maintaining the same amount of rest

00:49:51.980 | between sets for this same muscle group,

00:49:55.440 | by going from push, pull, push, pull of antagonistic muscles,

00:50:00.320 | you're able to have improved performance.

00:50:03.900 | And the reason for that has everything to do

00:50:06.100 | with what we were describing before,

00:50:08.060 | which is that typically if you were to do push, set, rest,

00:50:12.420 | push, set, rest, push, set, rest,

00:50:14.960 | well in between those sets,

00:50:17.420 | and in fact actually during those sets of pushing,

00:50:20.500 | the pulling muscles that would be involved in the chin ups

00:50:24.420 | or pull downs, et cetera, are actually relaxing,

00:50:27.700 | or at least are being released of some tension,

00:50:29.940 | including the activation of the spindles,

00:50:32.780 | among other things.

00:50:34.180 | So that's a long-winded way of saying

00:50:36.200 | that interleaving push and pull of antagonistic sets

00:50:40.280 | can leverage some of the same neural circuits

00:50:42.560 | that we're talking about leveraging

00:50:43.720 | for sake of increasing flexibility.

00:50:45.640 | Now, I offer this to you as a tool that you can try.

00:50:49.140 | One of the challenges with using this tool, however,

00:50:51.420 | is that you often have to occupy multiple sites

00:50:54.280 | within the gym.

00:50:56.140 | If you're doing this at home and you have your own gym,

00:50:57.980 | that's one thing.

00:50:58.940 | If you're doing this in a gym

00:50:59.820 | where you have multiple pieces of equipment,

00:51:01.600 | well, then you become that person

00:51:02.900 | who has essentially taken over some small corner

00:51:05.360 | or multiple corners or machines within the gym.

00:51:08.340 | And oftentimes you'll find that you'll walk back

00:51:10.080 | to a machine or you'll walk back

00:51:11.460 | to a given resistance exercise

00:51:13.540 | and someone has now taken it over

00:51:14.960 | and the whole thing could be thrown off.

00:51:16.180 | So it takes a little bit of orchestrating

00:51:18.580 | in order to do properly.

00:51:20.240 | But in general, what people find is that this can allow you

00:51:23.380 | to enhance performance overall of these individual movements

00:51:26.700 | again, while maintaining the same amount of rest.

00:51:30.920 | And even if you choose not to do this,

00:51:32.940 | I encourage you to pay attention to this as a concept

00:51:36.900 | because again, it's leveraging this idea

00:51:39.280 | of antagonistic muscles, flexors and extensors,

00:51:42.300 | antagonistic neural relationships

00:51:44.620 | between the spinal cord mechanisms

00:51:46.640 | that control one set of muscles

00:51:48.840 | and activating those muscles,

00:51:50.120 | allowing the opposite antagonistic muscle to relax

00:51:53.960 | and therefore to perform better on its next set.

00:51:57.580 | So now I'd like to shift to the question

00:51:59.120 | of what types of stretching can and should we do

00:52:01.840 | to increase limb range of motion?

00:52:04.340 | If our goal is to do that in the most efficient way possible

00:52:07.100 | 'cause I realized that most people don't have

00:52:09.380 | endless amounts of time to dedicate

00:52:10.900 | to a stretching practice.

00:52:12.180 | And even for those of us that do,

00:52:14.900 | I'm sure that you want to get the most outcome

00:52:18.040 | for a given effort.

00:52:19.700 | And what are the modes of stretching

00:52:21.580 | that are going to allow us to increase our flexibility

00:52:24.300 | and limb range of motion most safely?

00:52:27.100 | Now, there are a number of different types of stretching

00:52:29.060 | or methods of stretching.

00:52:31.000 | Broadly defined, we can describe these as dynamic,

00:52:35.960 | ballistic, static, and what's called PNF stretching.

00:52:40.640 | PNF stands for proprioceptive neuromuscular facilitation,

00:52:45.100 | and it involves and leverages many of the mechanisms

00:52:48.460 | that I described to you earlier.

00:52:50.080 | The first two that I mentioned,

00:52:51.100 | dynamic and ballistic stretching,

00:52:52.700 | both involve some degree of momentum

00:52:55.820 | and can be distinguished from static and PNF type stretching.

00:52:59.700 | Now, to distinguish dynamic stretching

00:53:02.020 | from ballistic stretching,

00:53:03.720 | like to focus on this element of momentum.

00:53:06.420 | Both involve moving a limb through a given range of motion.

00:53:11.340 | In dynamic stretching, however,

00:53:14.680 | it tends to be more controlled, less use of momentum,

00:53:17.400 | especially towards the end range of motion.

00:53:19.960 | Whereas in ballistic stretching,

00:53:22.080 | there tends to be a bit more swinging of the limb

00:53:25.540 | or use of momentum.

00:53:27.260 | So I invite you to visualize what dynamic and ballistic

00:53:29.980 | stretching might look like in your mind.

00:53:31.560 | You can even try it if it's safe for you to try it.

00:53:33.860 | Now, you could imagine, you're swinging your arm up overhead

00:53:36.780 | as much as possible and bringing it down.

00:53:38.300 | I'm doing this because I'm seated

00:53:39.500 | as kind of ridiculous movement to do well seated

00:53:41.440 | or perhaps at all.

00:53:42.840 | But for instance, you can see dynamic

00:53:45.200 | and ballistic stretching anytime someone, for instance,

00:53:47.880 | is holding onto something with one arm

00:53:49.820 | or maybe not holding on and swinging out their foot.

00:53:53.640 | So essentially getting movement about the hip joint.

00:53:57.680 | And you'll notice that some people raise it up

00:53:59.640 | and pause it and bring it down.

00:54:01.240 | That's one form of dynamic stretching.

00:54:03.800 | Whereas others will swing it up

00:54:07.160 | and sort of let it carry itself a bit further

00:54:10.280 | due to the momentum at the top of the movement

00:54:11.980 | and then just let it drop back down

00:54:13.360 | or maybe even control the descent.

00:54:14.940 | There is an enormous range of parameter space here

00:54:18.640 | or variables that one could imagine.

00:54:20.600 | And there's just simply no way

00:54:22.120 | that we could subdivide all those.

00:54:23.300 | But again, dynamic and ballistic stretching

00:54:25.440 | both involve movement.

00:54:27.640 | So we have to generate some force

00:54:29.240 | in order to create that movement.

00:54:31.460 | Ballistic stretching involving a bit more momentum

00:54:34.000 | or sometimes a lot more momentum,

00:54:35.440 | especially at the end range of motion.

00:54:38.040 | Now, both of those are highly distinct

00:54:40.120 | from static stretching,

00:54:41.380 | which involves holding the end range of motion.

00:54:44.200 | So minimizing the amount of momentum that's used.

00:54:47.000 | So to stay with a simple example

00:54:48.840 | that we are all now familiar with

00:54:50.840 | from our earlier discussion,

00:54:53.360 | slowly bending over at the waist

00:54:55.400 | and trying to touch your toes

00:54:57.420 | or putting your hands to the floor

00:54:59.320 | and then holding that end position

00:55:01.800 | before coming up in a slow and controlled way

00:55:05.260 | such that you reduce the amount of momentum to near zero

00:55:09.400 | would be one example of static stretching.

00:55:13.240 | Static stretching can be further subdivided

00:55:15.560 | into active or passive, right?

00:55:17.880 | There are different names for these kinds of approaches.

00:55:21.340 | You can hear about the Anderson approach

00:55:23.000 | or the Jonda approach.

00:55:24.020 | You can look these sorts of things up online.

00:55:26.040 | And again, people tend to name things after themselves.

00:55:28.100 | So some of these are proprietary

00:55:29.760 | related to specific programs.

00:55:31.060 | I'm not focusing on those.

00:55:32.380 | Others come to be named after the physiologists

00:55:34.620 | or the practitioners that initially popularized them.

00:55:38.140 | As is always the case,

00:55:39.520 | there's always a naming and renaming

00:55:41.060 | and claiming of territory with these things.

00:55:43.520 | For the time being,

00:55:44.360 | I'd like to just emphasize that static stretching

00:55:46.780 | can be both active

00:55:48.440 | where there's a dedicated effort

00:55:51.760 | on the part of the stretcher, you,

00:55:54.840 | to put force behind the hold

00:55:58.040 | to kind of extend

00:55:59.360 | or literally to extend the range of motion.

00:56:01.960 | And then there's also passive static stretching

00:56:05.760 | in which it's more of a relaxation

00:56:07.820 | into a further range of motion.

00:56:09.920 | And that can be a subtle distinction.

00:56:11.380 | And there are other ways

00:56:12.400 | in which we can further distinguish

00:56:13.700 | active and passive static stretching.

00:56:15.900 | But nonetheless, static stretching involves

00:56:18.660 | both those types of elements, active and passive,

00:56:21.380 | but is really about eliminating momentum.

00:56:24.220 | And then there's the PNF,

00:56:26.480 | the proprioceptive neuromuscular facilitation.

00:56:28.660 | And proprioception has several different meanings

00:56:31.760 | in the context of neuroscience and physiology.

00:56:34.400 | To just keep it really simple for today,

00:56:36.800 | proprioception involves both a knowledge and understanding

00:56:40.120 | of where our limbs are in space

00:56:42.740 | and relative to our body,

00:56:44.460 | typically relative to the midline.

00:56:45.880 | So the brain is often trying to figure out

00:56:48.020 | where are our limbs relative to our midline

00:56:50.720 | down the center of our body.

00:56:52.480 | And we know where our limbs are

00:56:54.880 | based on so-called proprioceptive feedback.

00:56:57.100 | So that's feedback that comes from sensory neurons, right?

00:57:00.800 | Now you know what sensory neurons

00:57:02.500 | that are essentially monitoring or responding to events

00:57:07.260 | within the joints, the connective tissue and the muscles.

00:57:11.280 | And within the deep components of the muscles,

00:57:14.920 | like the spindle reflex and within the tendons,

00:57:16.960 | like the GTO, the Golgi tendon organ.

00:57:20.060 | So PNF type stretching leverages these sorts of mechanisms,

00:57:25.060 | these neural circuits by way of, for instance,

00:57:29.940 | you would lie on your back.

00:57:32.100 | And if your goal is to increase your hamstring flexibility

00:57:35.300 | and the flexibility and range of motion

00:57:37.580 | of other related muscle systems,

00:57:40.160 | you might put a strap around your ankle

00:57:42.300 | and pull that muscle, or I should say, excuse me,

00:57:46.260 | that limb towards you.

00:57:47.460 | You're not going to pull the muscle towards you.

00:57:48.280 | You're going to pull that limb, your ankle towards you

00:57:50.380 | to try and get it sort of back over your head

00:57:52.620 | and then progressively relaxing into that,

00:57:55.500 | or maybe even putting some additional force

00:57:58.420 | to push the end range of motion and then relaxing it.

00:58:01.820 | And then actually trying to stretch that same limb

00:58:04.760 | or increase the limb range of motion without the strap.

00:58:08.520 | Sometimes these are assisted by other people.

00:58:11.500 | So people will even use loads.

00:58:13.700 | Sometimes they'll even use machines.

00:58:15.780 | There are a number of different apparati

00:58:17.660 | that have been designed for this.

00:58:18.900 | Sometimes it'll involve a training partner.

00:58:21.780 | There's a huge range of PNF protocols.

00:58:25.160 | And those protocols can be done both by oneself

00:58:28.900 | with or without straps, with machines,

00:58:30.860 | with actual weights or with training partners.

00:58:34.460 | If you're interested in the variation of exercises

00:58:36.900 | to say target your hamstrings versus your quadriceps

00:58:39.960 | versus your shoulders versus your chest muscles, et cetera,

00:58:42.600 | your neck muscles, and so on.

00:58:44.680 | There is an enormous range of information

00:58:47.640 | on dynamic ballistic static and PNF stretches

00:58:50.580 | for all the various muscle groups.

00:58:52.600 | And I should say there are some excellent books

00:58:55.300 | on those topics.

00:58:56.140 | There are also some excellent videos on YouTube

00:58:58.800 | and elsewhere.

00:58:59.860 | Nowadays, it's pretty easy to find exercises

00:59:03.300 | that allow you to target specific muscle groups,

00:59:06.820 | again, I encourage you to be safe in how you approach this.

00:59:09.300 | And I would encourage you also to pay attention

00:59:11.820 | to the information that soon follows

00:59:13.520 | as to what sorts of protocols one would use

00:59:15.940 | to apply those exercises.

00:59:17.780 | But the number of exercises and the availability

00:59:20.940 | of those exercises for targeting different muscle groups

00:59:23.220 | with these four different kinds of stretching

00:59:25.320 | is both immense and fortunately, thankfully,

00:59:29.860 | immediately accessible to all of us often at zero cost.

00:59:32.780 | So specific exercises to target specific muscle groups aside,

00:59:36.520 | we've now established that there are four major categories

00:59:39.860 | of stretching, or at least those are the four major

00:59:41.840 | categories I'm defining today.

00:59:43.660 | And we can further divide those categories

00:59:47.940 | into which are the ones that are going to be most effective

00:59:51.060 | for increasing range of motion in the longterm,

00:59:53.740 | not just in one individual session.

00:59:56.180 | And there've been a number of studies exploring this.

00:59:59.380 | I can list out at least four and we'll put those four

01:00:02.000 | as a kind of a cluster under one heading

01:00:04.300 | in the show note captions that arrive

01:00:07.280 | at essentially the same answer,

01:00:09.140 | which is that for increasing limb range of motion,

01:00:12.820 | it does appear that static type, including PNF,

01:00:17.600 | but static type stretching is going to be more effective

01:00:22.000 | than dynamic and ballistic stretching.

01:00:24.880 | So at least to my mind, this is good news.

01:00:28.660 | Why is it good news to me?

01:00:29.820 | Well, while dynamic and ballistic stretching

01:00:32.680 | can be immensely useful for improving performance

01:00:36.400 | of specific movements, in particular in the context

01:00:39.820 | of particular sports like tennis or in sprinting,

01:00:43.420 | or frankly, for any sport, they do carry with them

01:00:47.000 | a certain amount of risk because of the use of momentum.

01:00:50.440 | So you don't need to be highly trained

01:00:52.580 | in order to perform them.

01:00:53.660 | In fact, there is a place and we will describe

01:00:56.300 | when one would want to apply dynamic or ballistic stretching.

01:00:59.900 | I'll just give away for now.

01:01:01.800 | I think that most physios out there,

01:01:03.620 | and certainly the ones that I spoke to Dr. Andy Galpin,

01:01:07.020 | Dr. Kelly Starrett, and a few others point to the fact

01:01:11.380 | that doing some safe dynamic and ballistic stretching

01:01:16.380 | prior to say a resistance training session,

01:01:19.880 | or maybe even prior to a cardiovascular training session

01:01:23.300 | can be useful, both in terms of range of motion effects

01:01:27.500 | and in terms of neural activation effects.

01:01:30.540 | I don't want to use the words warm up

01:01:31.880 | because warming up is typically associated

01:01:33.800 | with increasing core body temperature as it should be,

01:01:36.980 | but for engaging the neural circuits

01:01:40.460 | and becoming familiarized with the neural circuits

01:01:43.180 | that you're about to use in other movements,

01:01:45.120 | while also increasing the range of motion

01:01:47.480 | of the joints involved in those movements

01:01:48.840 | so that you can perform them more safely

01:01:50.420 | and more confidently.

01:01:51.760 | So I'm certainly not saying, I want to repeat,

01:01:54.540 | I'm certainly not saying that dynamic

01:01:55.860 | and ballistic stretching are not useful.

01:01:57.480 | They absolutely are.

01:01:59.060 | But in terms of increasing limb range of motion

01:02:01.540 | in the long-term of truly becoming more flexible

01:02:06.140 | as opposed to transiently more flexible,

01:02:08.380 | static stretching, which includes PNF,

01:02:12.660 | appears to be the best route to go.

01:02:15.780 | So if your goal is to increase your limb range of motion

01:02:18.420 | for a given muscle group, or perhaps for all muscle groups,

01:02:21.800 | although you can imagine that'd be pretty tough.

01:02:23.600 | I mean, you're not going to spend time,

01:02:25.260 | I could imagine working on your tongue muscle control

01:02:28.320 | or neck muscle control and every muscle control,

01:02:30.980 | but most of us want to reduce so-called tightness,

01:02:34.100 | in air quotes, and increase limb range of motion

01:02:36.700 | for certain muscle groups.

01:02:38.500 | And it appears that the best way to do that

01:02:41.720 | is going to be static stretching of some kind,

01:02:44.420 | which raises the question of how often

01:02:46.560 | to do that static stretching

01:02:47.760 | and how long to hold those static stretches.

01:02:51.040 | And we can also ask the question,

01:02:52.840 | we should ask the question,

01:02:54.620 | where to hold those static stretches?

01:02:56.580 | Is it always a good idea to hold those static stretches

01:02:59.740 | at the end or the point of maximal range of motion?

01:03:04.140 | We're going to address that now.

01:03:05.560 | There's some terrific science around this.

01:03:07.660 | A slightly older study, but nonetheless a powerful one

01:03:10.940 | because it provided a foundation

01:03:12.760 | for a lot of subsequent work,

01:03:14.060 | which basically served to just confirm

01:03:15.960 | the answer they got here,

01:03:17.340 | is a study from Bandy et al, and the title of this study

01:03:21.540 | is "The Effect of Time and Frequency of Static Stretching

01:03:24.460 | on the Flexibility of the Hamstring Muscles."

01:03:27.740 | It's a study involving 93 subjects.

01:03:30.000 | So 61 men, 32 women, ranging in age from 21 to 39 years,

01:03:34.820 | so a pretty broad demographic,

01:03:37.220 | who had limited hamstring muscle flexibility,

01:03:39.640 | here I'm paraphrasing,

01:03:40.660 | and randomly assigned to one of five groups.

01:03:43.140 | So the four stretching groups stretched five days per week

01:03:47.520 | for six weeks.

01:03:48.360 | The fifth group, which served as a control, did not stretch.

01:03:51.500 | The results clearly show that, quote,

01:03:54.460 | "The change in flexibility appeared to be dependent

01:03:56.740 | on the duration and frequency of stretching."

01:03:58.700 | This is great.

01:03:59.540 | This tells us that stretching for a given amount of time

01:04:02.620 | scales with the amount of limb range of motion improvement

01:04:05.700 | that one will see.

01:04:06.820 | There were many interesting findings within this study,

01:04:09.500 | but the one that I'd like to highlight most is, quote,

01:04:13.060 | "The results of this study suggest

01:04:14.780 | that a 30-second duration is an effective amount of time

01:04:18.720 | to sustain a hamstring muscle stretch

01:04:20.560 | in order to increase range of motion.

01:04:23.320 | No increase in flexibility occurred

01:04:25.460 | when the duration of stretching was increased

01:04:27.300 | from 30 seconds to 60 seconds,

01:04:30.240 | or when the frequency of stretching was increased

01:04:32.560 | from one to three times per day."

01:04:35.060 | Okay, so now we're starting to lay down some parameters.

01:04:38.280 | What this study reveals and what subsequent studies tell us,

01:04:41.480 | and we will get into those subsequent studies,

01:04:44.100 | is that ideally one would do static stretches

01:04:48.340 | that are held for 30 seconds,

01:04:51.740 | perhaps more in certain instances,

01:04:53.400 | and I'll explain when that can be useful,

01:04:55.180 | but here, holding those stretches for more than 30 seconds

01:04:59.420 | did not turn out to be additionally useful.

01:05:02.580 | So if you're going to stretch your quadricep, for instance,

01:05:04.860 | and you're going to hold that stretch in static fashion,

01:05:07.540 | remember, not using momentum,

01:05:09.860 | and you can use the mental tricks

01:05:12.580 | of either trying to push through the pain,

01:05:14.840 | which I don't recommend necessarily.

01:05:17.000 | I think that makes us prone to injury,

01:05:19.560 | or to relax into the stretch,

01:05:21.200 | but nonetheless, providing some force,

01:05:23.480 | typically with a hand in order to pull your ankle back

01:05:26.600 | if you're doing a quadricep stretch.

01:05:27.860 | Some people might do this on the edge of a sofa.

01:05:29.760 | Remember, there are a lot of different exercises

01:05:31.600 | and ways to do this that you can explore elsewhere.

01:05:34.260 | Well, holding that static stretch for 30 seconds

01:05:37.720 | appears to be sufficient to stimulate an increase

01:05:41.800 | in limb range of motion over time.

01:05:44.060 | Again, these are protocols

01:05:44.960 | that were used repeatedly over time,

01:05:46.360 | and we'll talk about how often to repeat them

01:05:48.640 | in order to get maximum effect.

01:05:50.260 | But 30 second holds for static stretches

01:05:52.920 | is the number that I think we want to focus on,

01:05:54.820 | and that most of us are going to want to utilize.

01:05:56.940 | So now let's explore how many sets of static stretching

01:06:00.860 | one ought to do in order to get

01:06:03.380 | a maximum range of motion improvement

01:06:06.140 | while not placing us into a system

01:06:08.740 | that's going to create injury,

01:06:10.260 | nor a situation where we have to be

01:06:12.860 | constantly stretching throughout the day,

01:06:14.700 | because again, most of us don't have time to do that.

01:06:17.120 | This issue of sets is an important one.

01:06:19.500 | In the context of cardiovascular exercise,

01:06:21.500 | we've talked about the data that support the fact

01:06:24.460 | that doing at least 150,

01:06:27.700 | and ideally as much as 200 minutes per week

01:06:30.300 | of zone two cardiovascular exercise

01:06:32.340 | is very useful for cardiovascular health

01:06:34.120 | and for other aspects of health.

01:06:35.860 | And of course, there are other aspects

01:06:36.960 | of cardiovascular exercise that could be layered

01:06:38.900 | onto and into that that can be useful,

01:06:40.680 | like 90 second maximal sprints, et cetera,

01:06:43.340 | discussed this a lot in the episode with Dr. Andy Galpin

01:06:46.220 | and on our episode about endurance.

01:06:48.180 | And we also talked about sets in the context

01:06:50.860 | of strength and hypertrophy building,

01:06:52.800 | building muscle size and or strength

01:06:55.380 | in the episode about that,

01:06:57.300 | and in particular in the episode with Dr. Andy Galpin.

01:07:00.140 | And there, we could also arrive at some specific parameters,

01:07:03.000 | and it's going to vary, of course, between individuals,

01:07:05.700 | depending on how hard you train,

01:07:07.100 | whether or not you take sets to failure,

01:07:08.740 | your repetition range, et cetera.

01:07:10.580 | But in the context of strength and hypertrophy building,

01:07:12.980 | we arrived at approximately six,

01:07:16.740 | maybe as many as 10 sets per week per muscle group.

01:07:19.860 | Some of that work is done as direct work

01:07:21.620 | to a given muscle group.

01:07:22.820 | Some of that work is indirect.

01:07:24.300 | So doing a certain pulling exercise, of course,

01:07:26.300 | will target the latissimus dorsi muscles,

01:07:30.960 | but also the biceps.

01:07:31.980 | So that doesn't necessarily mean you have to do 10 sets

01:07:34.940 | for the biceps and for the lats.

01:07:36.460 | Sometimes you're getting some indirect work, et cetera.

01:07:38.340 | All of that was delineated in the episode

01:07:40.300 | with Dr. Andy Galpin.

01:07:41.740 | And we arrived at those numbers of sets

01:07:44.300 | according to the same criteria that we will apply here.

01:07:47.320 | What is the minimum number of sets both to maintain

01:07:52.120 | and to improve a given mode of performance?

01:07:56.620 | Strength and hypertrophy or cardiovascular health.

01:07:59.340 | Again, to either maintain or improve.

01:08:01.300 | And we can do the same thing for improving

01:08:04.340 | or maintaining range of motion.

01:08:06.220 | Because as I mentioned earlier,

01:08:07.740 | the data points to the fact that if we don't do

01:08:10.300 | some dedicated work to improve range of motion over time,

01:08:13.740 | we will lose our flexibility and limb range of motion

01:08:17.240 | over time, just by virtue of the fact

01:08:19.640 | that we're not doing anything to offset that.

01:08:21.700 | So whether or not you want to maintain, reestablish,

01:08:25.620 | or gain limb range of motion,

01:08:29.060 | static stretching of holds of 30 seconds appear to be best.

01:08:33.940 | Now the question is, how long should you do that?

01:08:36.860 | And how many sets should you do that?

01:08:37.700 | And how many times a week should you do that?

01:08:40.180 | And to answer those questions,

01:08:42.300 | I'm going to turn to what I think

01:08:43.740 | is a really spectacular review.

01:08:45.420 | This was a review that was published in the year 2018.

01:08:48.100 | So it's fairly recent.

01:08:49.300 | First author, Thomas, Edwin Thomas, last author, Palma.

01:08:52.880 | We will put a link to this in the show note caption.

01:08:55.060 | The title of the paper is the relation

01:08:56.920 | between stretching typology and stretching duration,

01:08:59.800 | the effects on range of motion.

01:09:01.340 | It's a very straightforward title.

01:09:03.060 | This is a review article that explored

01:09:07.340 | a number of different studies.

01:09:09.520 | Had criteria for whether or not those studies

01:09:12.060 | could be evaluated in the context of the questions here.

01:09:15.480 | Had some quality standards and some other standards

01:09:17.600 | that they applied.

01:09:18.440 | And basically winnowed down a large collection of studies

01:09:22.400 | to a remaining 23 articles that were able

01:09:25.400 | to be considered, quote, eligible and included

01:09:28.360 | in the quantitative synthesis done here.

01:09:30.880 | So key points from that quantification

01:09:34.960 | and synthesis done in this paper.

01:09:37.080 | First of all, and I quote, all stretching typologies

01:09:40.120 | showed range of motion improvements over a long-term period.

01:09:43.200 | However, the static protocols showed significant gains

01:09:46.920 | with a P value less than 0.05,

01:09:48.560 | which means a probability that cannot be explained

01:09:52.200 | by chance alone when compared to ballistic or PNF protocols.

01:09:56.480 | So again, what we're hearing is that static stretching

01:09:58.680 | is the preferred mode for increasing limb range of motion.

01:10:02.040 | Although here they make the additional point

01:10:04.620 | that static stretching might even be superior,

01:10:07.700 | not just to ballistic stretching, but also to PNF protocols.

01:10:12.700 | Because before, as you may recall,

01:10:15.000 | there was a distinction between ballistic and dynamic

01:10:19.940 | and static and PNF.

01:10:21.300 | And so here it appears again that static stretching

01:10:24.240 | is sort of rising to the top of the list

01:10:27.240 | as the optimal approach relative

01:10:29.040 | to all other stretching approaches,

01:10:31.700 | at least in the context of increasing limb range of motion.

01:10:34.880 | The authors go on to say time spent stretching per week

01:10:39.760 | seems fundamental to elicit range of movement improvements

01:10:42.700 | when stretches are applied for at least

01:10:44.800 | or more than five minutes per week.

01:10:47.680 | Okay, this is critical.

01:10:48.860 | This is not five minutes per stretch.

01:10:50.900 | Remember, 30 seconds per static stretch,

01:10:53.080 | but at least five minutes per week.

01:10:55.440 | Whereas the time spent stretching within a single session

01:10:58.660 | does not seem to have a significant effects

01:11:00.440 | for range of motion gains.

01:11:01.600 | If this is getting confusing,

01:11:02.940 | I'll make sure that you soon understand

01:11:04.980 | exactly what we can export from these conclusions.

01:11:08.100 | The data indicate that performing stretching

01:11:11.700 | at least five days a week,

01:11:13.720 | now some of you may already be groaning,

01:11:16.620 | for at least five minutes per week.

01:11:18.740 | Okay, so five days per week, that's a lot,

01:11:21.100 | but at least five minutes per week,

01:11:23.160 | five minutes per week is not that much,

01:11:25.020 | using static stretching may be beneficial

01:11:27.360 | to promote range of motion improvements.

01:11:30.240 | Okay, I've read this study in detail now.

01:11:33.000 | They highlight again, the reduction in flexibility

01:11:35.300 | that occurs from 20 to 49 years of age and so on,

01:11:38.820 | how acute bouts of short-term stretching

01:11:41.080 | up to three weeks can improve stretch tolerance.

01:11:43.380 | I think that's a key point that in the short term,

01:11:45.980 | the first three weeks of embarking

01:11:47.360 | on a stretching and flexibility program,

01:11:49.980 | much of the improvements

01:11:51.180 | come from the short-term neural improvements

01:11:53.100 | that we talked about before

01:11:54.080 | of inhibiting the spindle reflex and so on,

01:11:55.940 | and also a stretch tolerance,

01:11:57.540 | a comfort with doing the movements

01:11:59.060 | and maybe even a comfort in overriding

01:12:00.660 | some of the pain mechanisms.

01:12:01.740 | I'll talk a little bit more about that in just a bit

01:12:04.140 | and the particular utility of yoga,

01:12:07.700 | something that I don't often practice,

01:12:09.820 | but that after reading this article

01:12:11.340 | that I'll mention in a little bit,

01:12:12.700 | I'm considering perhaps taking up

01:12:14.420 | some form of yoga protocol.

01:12:17.260 | Now, I've already highlighted

01:12:18.380 | some of the key takeaways from the study,

01:12:20.660 | namely that we need to get at least five minutes per week

01:12:25.100 | of static stretching per muscle group.

01:12:27.680 | And based on the previous paper that we talked about,

01:12:31.940 | we need to divide that five minutes

01:12:33.540 | into sets of 30 seconds each.

01:12:36.580 | And as I mentioned earlier,

01:12:38.660 | it doesn't seem to be the case

01:12:40.060 | that you can do all of that in one day, unfortunately.

01:12:44.100 | It does seem important that the frequency

01:12:46.340 | of stretching practice distributed

01:12:48.060 | throughout the week is important.

01:12:50.080 | So let's talk protocols.

01:12:52.140 | We are now talking about doing static stretching,

01:12:54.240 | so holding, so limiting momentum,

01:12:56.000 | and holding a stretch for 30 seconds per set.

01:12:58.460 | We're talking about trying to achieve

01:13:00.980 | five minutes per week of those static holds,

01:13:03.980 | but that we can't do it all in one session

01:13:08.020 | because the frequency of sessions

01:13:10.120 | distributed throughout the week correlates

01:13:12.000 | with the improvements in limb range of motion.

01:13:14.360 | So what this means is that we should probably be doing

01:13:17.640 | anywhere from two to four sets

01:13:20.620 | of 30-second static hold stretches,

01:13:25.380 | five days per week, or some variant thereof.

01:13:29.620 | And I do say some variant thereof,

01:13:31.540 | because it turns out that even though

01:13:32.860 | there was that earlier study that we talked about,

01:13:35.140 | that holding a stretch for more than 30 seconds,

01:13:37.940 | in that case, 60 seconds,

01:13:39.540 | didn't turn out to be additionally beneficial.

01:13:42.360 | It appears that if you do hold those stretches

01:13:45.020 | for 60 seconds per static stretching set, for instance,

01:13:49.040 | you can get away with stretching fewer days per week overall.

01:13:53.420 | So in order to make this as clear as possible,

01:13:56.900 | 'cause I do realize there are a lot of parameters,

01:13:59.300 | and you might be asking,

01:14:00.500 | why didn't you just make me a list

01:14:01.660 | of the exact things I should do?

01:14:03.020 | Well, it doesn't work that way,

01:14:04.120 | because once you understand the mechanisms

01:14:06.100 | and once you understand your particular goals,

01:14:08.400 | this information is designed for you to be able

01:14:10.660 | to construct a stretching program

01:14:12.340 | that is tailored to your specific goals.

01:14:14.580 | If I just gave you the stretching program that I'm doing,

01:14:16.940 | or I should say that I'm soon to be doing,

01:14:18.500 | 'cause I'm soon to be doing one

01:14:19.780 | based on the research for this particular episode,

01:14:23.540 | well, that wouldn't be beneficial for you.

01:14:25.460 | Because for instance, if you have very flexible hamstrings,

01:14:28.340 | but not very flexible quadriceps,

01:14:30.300 | or you are somebody who is engaged in sport

01:14:32.920 | or not engaged in sport,

01:14:34.900 | what you need to do is going to vary somewhat.

01:14:36.920 | So what would effective stretching protocol look like?

01:14:40.340 | We're all trying to improve limb range of motion

01:14:42.580 | for different limbs and different muscle groups,

01:14:45.900 | but just by way of example,

01:14:47.160 | and that's because the one we've been using,

01:14:48.400 | let's talk about hamstrings for the time being.

01:14:51.540 | This could of course be applied to other muscle groups.

01:14:54.240 | Let's say you want to improve hamstring flexibility

01:14:57.040 | and limb range of motion about and around the hamstring

01:15:00.000 | and involving the hamstring.

01:15:02.400 | You would want to do three sets

01:15:06.720 | of static stretching for the hamstring.

01:15:09.020 | Again, easy to find such exercises on the internet.

01:15:11.880 | You would do that by holding the stretch for 30 seconds,

01:15:18.180 | resting some period of time and doing it again,

01:15:20.480 | holding for 30 seconds, resting some period of time,

01:15:23.100 | and then holding it for 30 seconds.

01:15:26.260 | That would be one training session for the hamstrings.

01:15:28.700 | I have to imagine that you'd probably want to stretch

01:15:30.780 | other muscle groups as well in that same session.

01:15:33.520 | Although at least as far as I could tell,

01:15:34.940 | there were no data pointing to the fact

01:15:36.940 | that you couldn't do your hamstring stretching

01:15:38.860 | one part of the day

01:15:39.700 | and your quadriceps stretching another part of the day,

01:15:41.980 | but presumably you're going to want to combine

01:15:44.180 | your flexibility training into one single session.

01:15:47.900 | So three sets of 30 seconds each, you get 90 seconds,

01:15:52.900 | and you would do that ideally five times a week

01:15:56.940 | or maybe even more because it does seem like frequency

01:15:59.700 | distributed throughout the week is an important parameter.

01:16:01.980 | Now, one thing that we have not highlighted

01:16:04.440 | or at least described is how long to rest

01:16:07.180 | between stretching sets.

01:16:09.140 | And despite my efforts,

01:16:11.300 | I could not find research back information

01:16:15.540 | that pointed to whether or not 30 seconds of rest

01:16:18.740 | for every 30 seconds stretching

01:16:20.140 | or 60 seconds rest for every 30 seconds stretching

01:16:23.480 | was ideal.

01:16:24.780 | I think it's reasonable to assume that

01:16:26.980 | doubling the amount of time for the interleaving rest

01:16:30.700 | would be appropriate or at least doable.

01:16:33.700 | If anyone out there has knowledge about rest

01:16:35.940 | between stretching sets and has some physiology

01:16:39.420 | or some biology or some experiential information

01:16:42.700 | as to why a given ratio of duration of static stretch

01:16:46.980 | to rest in between static stretch sets ought to be used,

01:16:50.220 | please put it in the comments on YouTube.

01:16:52.380 | That'd be a terrific way for us to get that information.

01:16:54.460 | I'd love to do any follow-up to links that you provide

01:16:57.220 | and so on.

01:16:58.620 | But now we're starting to build into a protocol

01:17:02.060 | that is backed by the scientific data.

01:17:04.900 | Three sets of 30 seconds of holds done five times

01:17:08.940 | or maybe even six times per week.

01:17:11.380 | One thing that did show up in my exploration

01:17:14.740 | of the peer-reviewed research

01:17:16.260 | is this notion of warming up for all this.

01:17:18.360 | We haven't talked about that yet.

01:17:20.720 | In general, to avoid injury,

01:17:22.120 | it's a good idea to raise your core body temperature a bit

01:17:24.420 | before doing these kinds of stretches,

01:17:27.100 | even these static stretches,

01:17:28.420 | which we can sort of ease into

01:17:29.860 | and don't involve ballistic movement by definition.

01:17:33.820 | And the basic takeaway that I was able to find was

01:17:38.020 | that if we are already warm from running

01:17:41.220 | or from weight training or from some other activity,

01:17:44.440 | that doing the static stretching practice

01:17:47.140 | at the end of that weight training or cardiovascular

01:17:50.300 | or other physical session

01:17:51.860 | would allow us to go immediately into the stretching session

01:17:55.560 | because we're already warm, so to speak.

01:17:57.820 | Otherwise, raising one's core body temperature by a bit

01:18:01.540 | by doing five to seven, maybe even 10 minutes

01:18:04.620 | of easy cardiovascular exercise or calisthenic movements,

01:18:08.420 | provided you can do those without getting injured.

01:18:11.100 | Seems to be an ideal way to warm up the body for stretching.

01:18:13.680 | We should be warm or warm up to stretch,

01:18:16.520 | although those warmups don't have to be extremely extensive.

01:18:19.220 | And then just by way of logic,

01:18:20.860 | doing the static stretching after resistance training

01:18:23.640 | or cardiovascular training seems to be most beneficial.

01:18:26.300 | In fact, and unfortunately,

01:18:27.860 | we don't have time to go into this in too much detail today,

01:18:30.420 | I was able to find a number of papers that make the argument

01:18:34.220 | that static stretching prior to cardiovascular training

01:18:38.060 | and maybe even prior to resistance training

01:18:41.800 | can limit our performance

01:18:43.580 | in running and resistance training.

01:18:46.060 | I realize that's a controversial area.

01:18:48.260 | You have those who say, no, it's immensely beneficial.

01:18:51.300 | You have those who say, no, it inhibits performance.

01:18:53.780 | And those that say, no,

01:18:55.100 | it's a matter of how exactly you perform

01:18:57.200 | that static stretching and which muscle groups

01:18:59.300 | and how you're doing this and how much time in between

01:19:02.340 | static stretching and performance.

01:19:03.700 | But to leave all that aside,

01:19:05.660 | doing static stretching after some other form of exercise,

01:19:09.540 | and if not after some form of exercise,

01:19:12.820 | after a brief warmup to raise your core body temperature,

01:19:15.500 | definitely seems like the right way to go.

01:19:17.500 | Now for some of you out there, and I confess for me as well,

01:19:20.680 | doing something five days a week

01:19:22.140 | seems like a big commitment,

01:19:23.180 | even if that commitment is one to only do three sets

01:19:25.980 | of 30 second static stretches.

01:19:28.820 | I say this because you've got the warmup.

01:19:31.300 | I generally like to bring a kind of a focus

01:19:33.460 | and dedication to a practice.

01:19:35.060 | And of course, because when doing these kinds of protocols,

01:19:39.100 | it's likely that you're not just stretching your hamstrings.

01:19:41.940 | So it's not just 90 seconds of work

01:19:43.660 | with a minute of rest in between,

01:19:45.540 | but very likely that we're also doing quadriceps stretching

01:19:48.440 | and also doing stretching for the shoulders

01:19:50.220 | and stretching for the back and the neck and so on.

01:19:52.300 | And so that entire session is going to take some time.

01:19:54.940 | And five days a week is a pretty serious commitment for most,

01:19:57.460 | especially for those of us that don't exercise

01:20:00.200 | or do athletics for a living, which I don't.

01:20:03.620 | So there is some evidence from the literature

01:20:06.340 | that one can get away with,

01:20:08.020 | or I don't even know that we should think about it

01:20:09.660 | as getting away with,

01:20:10.500 | but that one can do longer hold static stretches

01:20:14.100 | of up to say 60 seconds,

01:20:17.260 | but do fewer total sessions per week.

01:20:20.920 | So rather than three 30 second static holds,

01:20:24.220 | doing three 60 second static holds

01:20:27.480 | and doing those every other day.

01:20:30.100 | And there really hasn't been

01:20:31.540 | a systematic exploration of this.

01:20:33.100 | The article that I was referring to just a few moments ago,

01:20:36.180 | this analysis of the 23 articles

01:20:40.700 | was combined into this enormous set of tables

01:20:43.100 | and some really quite nice graphs

01:20:45.300 | that you're welcome to look at

01:20:46.740 | since we're going to provide a link to the study.

01:20:49.060 | There are a couple of key takeaways that I want to mention

01:20:52.060 | that are separate from this issue of

01:20:53.720 | how long to stretch and how often.

01:20:55.940 | First of all, they describe in their discussion

01:20:59.600 | that there were improvements in range of motion

01:21:03.300 | independent of whether or not people did

01:21:05.920 | static stretching, active stretching,

01:21:07.920 | passive stretching, ballistic stretching, or PNF stretching.

01:21:11.920 | So all of those forms of stretching

01:21:13.600 | will improve limb range of motion.

01:21:15.480 | This is essential to point out,

01:21:17.140 | and I want to emphasize this.

01:21:19.280 | Static stretching, however,

01:21:20.820 | gave the greatest degree of gains in limb range of motion.

01:21:25.920 | And on average, they saw a 20.9% increase,

01:21:29.760 | but some of the other increases they observed

01:21:32.200 | were also quite substantial.

01:21:34.140 | So ballistic stretching can also provide

01:21:36.640 | some pretty impressive limb range of motion improvements.

01:21:40.480 | However, they tended to be in the range of,

01:21:43.240 | here they point out 11.65% increase,

01:21:45.920 | or in the case of PNF, a 15% increase.

01:21:48.360 | So it appears that the greatest improvements

01:21:51.260 | in limb range of motion for your time spent and effort spent

01:21:55.160 | is going to be this minimum of five minutes per week

01:21:58.560 | to elicit a significant response,

01:22:00.100 | with five days being the minimum

01:22:01.640 | weekly recommended frequency

01:22:03.220 | to achieve significant range of motion improvements.

01:22:07.420 | I confess this was pretty surprising to me

01:22:10.320 | when I compare flexibility training to, say,

01:22:13.960 | resistance training for strength and hypertrophy.

01:22:16.360 | I've had the experience,

01:22:17.360 | and I know that other people have had the experience,

01:22:19.080 | and I think Dr. Andy Galpin would probably agree that,

01:22:23.700 | provided one trains hard enough and appropriately,

01:22:27.060 | that you don't need to train resistance training

01:22:30.680 | five days a week in order to get significant improvements

01:22:33.740 | in strength and hypertrophy.

01:22:34.840 | Some people might need to,

01:22:36.180 | but you can get a lot of positive results

01:22:39.080 | in those variables with less frequent training,

01:22:42.160 | certainly with three or four days a week of training.

01:22:45.600 | And for cardiovascular training,

01:22:47.260 | I'm not aware of anyone having tested

01:22:49.200 | whether or not one very long run each week

01:22:51.380 | can actually increase cardiovascular fitness

01:22:53.240 | and you're not doing anything else,

01:22:54.260 | although I have to imagine you'd probably see

01:22:55.940 | some improvement compared to not doing anything.

01:22:58.020 | But most people are doing repeated training sessions

01:23:01.620 | of cardiovascular strength training.

01:23:04.100 | Not a lot of people are doing five days a week

01:23:06.860 | of strength training, at least that I'm aware of.

01:23:09.500 | Some people are, but most people I think are not.

01:23:12.140 | And some people are doing five or more days a week

01:23:15.400 | of cardiovascular training.

01:23:17.400 | I'm guessing that most people are not doing

01:23:19.640 | five days a week of dedicated static stretch

01:23:22.640 | range of motion directed training.

01:23:25.740 | But it does appear that that frequency about the week,

01:23:29.220 | getting those repeated sessions,

01:23:30.440 | even if they are short for an individual muscle group,

01:23:32.780 | turns out to be important.

01:23:34.020 | And so that points to the, perhaps the reason

01:23:37.460 | why so few people are doing dedicated range of motion work.

01:23:40.480 | But it also reminds me that all of the studies

01:23:44.560 | that were described, at least in this review,

01:23:46.620 | and some of the other ones that were not,

01:23:48.700 | really show impressive changes in limb range of motion.

01:23:52.120 | I mean, 20 plus percent, or even 15% with PNF.

01:23:56.140 | I mean, these are big changes that are going to benefit us.

01:23:59.040 | They're going to offset the age-related losses

01:24:01.460 | in flexibility for sure,

01:24:03.280 | if one is dedicated about these practices.

01:24:05.540 | And in many cases,

01:24:07.260 | they're going to increase limb range of motion

01:24:09.460 | in ways that are going to allow us better performance

01:24:12.260 | in certain physical endeavors, certainly better balance.

01:24:15.140 | Or we haven't really talked about balance and stability,

01:24:17.300 | but range of motion can impair balance and stability

01:24:21.180 | in some extreme circumstances.

01:24:22.720 | But by and large, limb range of motion,

01:24:24.760 | lack of tightness, improved posture,

01:24:26.420 | improved physical performance, excuse me,

01:24:29.260 | and things of that sort is something

01:24:31.380 | that I think we can all benefit from

01:24:32.940 | and that are key features of longevity.

01:24:35.600 | We don't often think of them

01:24:36.620 | because we so prioritize cardiovascular health

01:24:38.980 | and the relationship between the heart and brain health

01:24:40.920 | and resistance training and musculoskeletal hypertrophy

01:24:45.820 | or strength, et cetera.

01:24:47.120 | But as I delved into this literature,

01:24:49.420 | it really highlighted for me the extent to which

01:24:52.140 | having really good limb range of motion,

01:24:54.780 | at least maintaining limb range of motion

01:24:56.880 | as we age from year to year,

01:24:58.980 | and maybe even improving limb range of motion

01:25:01.380 | can be immensely beneficial for reducing pain,

01:25:04.700 | for again, improving posture,

01:25:07.140 | improving our ability to perform, to walk, et cetera.

01:25:10.360 | And indeed there's a whole literature

01:25:12.400 | that relates our limb range of motion

01:25:14.640 | to things like pain management

01:25:16.380 | of things related to headache and so on and so forth.

01:25:19.140 | So limb range of motion is not just about

01:25:21.760 | becoming a contortionist

01:25:22.980 | or being able to complete the yoga class.

01:25:25.300 | It really is about maintaining the integrity

01:25:27.320 | and the health of the neuromuscular system,

01:25:29.980 | the connective tissue,

01:25:31.340 | and the neuromuscular connective network,

01:25:33.840 | because those are indeed working

01:25:35.300 | as an ecosystem and a network.

01:25:37.140 | I'd like to just briefly touch on PNF stretching

01:25:40.020 | for a moment.

01:25:40.860 | Again, this is a vast landscape with many parameters

01:25:44.820 | and different practitioners,

01:25:45.780 | a lot of competing opinions out there to put it lightly.

01:25:50.780 | Nonetheless, I do want to emphasize

01:25:54.340 | that the PNF training leverages those spindle mechanisms

01:25:57.480 | and GTO mechanisms that we talked about earlier.

01:26:00.540 | But I realized that in describing

01:26:02.420 | the quadricep contraction hamstring stretch,

01:26:05.920 | little mini experiment that hopefully you did,

01:26:08.720 | that I didn't really highlight the role of the GTOs,

01:26:11.220 | the Golgi tendon organs that much.

01:26:13.220 | And I just would like to just briefly do that for a moment.

01:26:16.220 | The GTOs have multiple functions.

01:26:20.300 | In fact, I think even though GTOs

01:26:22.060 | are in every medical textbook, every physiology textbook,

01:26:24.740 | every first year neuroscientist learns about them

01:26:27.640 | when learning about the neuromuscular junctions

01:26:29.420 | and the mechanisms of interoception, et cetera,

01:26:32.160 | they are likely to have other functions as well.

01:26:34.660 | And one of the reasons why PNF stretching does work,

01:26:38.200 | whether or not you're doing that by using a strap

01:26:42.260 | to pull back a limb

01:26:43.980 | or whether or not you're actively contracting

01:26:46.420 | your quadriceps to then release

01:26:48.620 | and emphasize stretch range of motion

01:26:51.420 | for your hamstrings and related muscle groups

01:26:54.140 | is that activation of those GTOs,

01:26:58.020 | meaning putting loads and tension into that system,

01:27:02.500 | can inhibit the spindles

01:27:04.780 | in the opposite antagonistic muscle groups.

01:27:07.980 | And so one of the reasons why flexing,

01:27:11.280 | or I should say contracting your quadriceps

01:27:14.460 | really intensely for some period of time

01:27:16.720 | allows your hamstrings to subsequently experience

01:27:19.940 | greater range of motion.

01:27:21.600 | And again, it's not just the hamstrings,

01:27:22.980 | but the related connective tissue

01:27:24.760 | and neural circuits, et cetera,

01:27:27.140 | is because yes, it's quote unquote relaxing

01:27:32.060 | the hamstrings and the spindle,

01:27:34.240 | but there's also a direct relationship

01:27:37.920 | between activation of the GTOs in the quadricep

01:27:42.060 | and release of the spindles

01:27:45.740 | in the hamstring and related muscles.

01:27:47.380 | This has a name, it's called autogenic inhibition.

01:27:49.900 | It's a fancy name for contraction of one muscle group,

01:27:53.700 | providing a relaxation of the other muscle group

01:27:56.280 | that's antagonistic to it.

01:27:59.260 | And it relates back to this idea

01:28:00.900 | of interleaving sets in the gym.

01:28:02.620 | So if you think back to that example,

01:28:05.020 | now it should make sense as to why, for instance,

01:28:08.280 | if you do, let's say a set of bench presses

01:28:10.760 | or shoulder presses,

01:28:12.060 | and let's say you get 10 repetitions

01:28:14.460 | and you fail on the 11th,

01:28:16.020 | that muscle is very, very fatigued.

01:28:18.300 | If you were to rest some period of time

01:28:20.220 | and then go back and do another set,

01:28:21.980 | well, during the rest, that muscle group has been relaxing.

01:28:26.100 | It's obviously not contracting the same way it was

01:28:27.940 | during the resistance set.

01:28:29.820 | But by going and doing a pulling exercise

01:28:32.540 | that involves the antagonistic muscle group,

01:28:34.500 | so strongly contracting the back muscles through a pull,

01:28:37.320 | like a pull down or a chin up or a row type exercise,

01:28:41.620 | you're activating or near activating the GTO system

01:28:45.980 | in those pulling muscles

01:28:47.220 | in a way that provides autogenic inhibition

01:28:50.940 | for the pushing muscles.

01:28:52.760 | Now, again, the physios out there

01:28:55.480 | are probably either screaming or banging their heads

01:28:58.100 | against whatever sound system

01:28:59.940 | this happens to be arriving through to them saying, wait,

01:29:02.660 | but in many cases, the GTOs aren't activated enough

01:29:05.800 | to provide that autogenic inhibition.

01:29:07.580 | That's true, but even the sub-threshold activation

01:29:11.660 | of those intraspinal circuits,

01:29:13.480 | so the place where the GTO circuit

01:29:15.700 | and the spindle circuit interact,

01:29:17.500 | can provide an additional replenishment

01:29:20.860 | of say the pushing muscles

01:29:22.900 | while you're activating those pulling muscles.

01:29:24.700 | And this is at least one, not the only,

01:29:26.660 | but at least one mechanisms

01:29:28.040 | by which interleaving push and pull, push and pull

01:29:30.940 | for both strength and hypertrophy training,

01:29:33.060 | but also for range of motion stretching type training

01:29:37.540 | can allow you to achieve better results

01:29:40.620 | in a shorter period of time.

01:29:42.280 | And I raise this because I want to keep in mind

01:29:44.940 | the efficiency of any training program.

01:29:47.220 | We just a moment ago established that doing, for example,

01:29:50.980 | three sets of 30 second static holds

01:29:53.280 | can be very useful for the hamstrings with,

01:29:55.780 | let's just say for sake of simplicity and practicality,

01:29:58.980 | a minute's rest in between.

01:30:00.620 | But during that minute's rest,

01:30:02.500 | you can stretch the opposite antagonistic muscle group,

01:30:06.340 | such as the quadriceps.

01:30:08.340 | Or if you want to use PNF training,

01:30:10.740 | you could do loading of the quadriceps in between.

01:30:13.780 | So there are a number of different ways

01:30:15.020 | in which you can start to interleave static stretching

01:30:19.100 | with PNF stretching.

01:30:20.840 | You can start to interleave even PNF type protocols

01:30:24.500 | with resistance training,

01:30:25.520 | although that gets a bit more complicated.

01:30:27.760 | You can really start to construct

01:30:29.220 | and build protocols that are ideal for you.

01:30:31.800 | What we will do is for an upcoming neural network newsletter.

01:30:36.840 | So for those of you that aren't familiar,

01:30:38.160 | the Huberman Lab podcast

01:30:39.180 | has a so-called neural network newsletter.

01:30:40.920 | These are monthly newsletters

01:30:42.160 | where we put distilled points from the podcast

01:30:45.400 | and oftentimes protocols in a downloadable PDF form.

01:30:48.860 | You can access it by giving us your email.

01:30:50.380 | We don't share your email with anybody.

01:30:51.900 | If you want to see examples of these,

01:30:53.060 | you can go to HubermanLab.com

01:30:54.560 | and go to the menu and see newsletter.

01:30:56.260 | You don't have to sign up for anything

01:30:57.360 | to see examples of what these are like.

01:30:59.500 | I'll provide a couple of different protocols,

01:31:01.880 | one that is pure static stretching,

01:31:04.620 | one that involves PNF type stretching,

01:31:07.800 | and I'll also put down a protocol

01:31:10.800 | that involves the antagonistic interleaved muscle training

01:31:13.980 | of the sort that I've been describing

01:31:15.180 | a few times throughout this episode.

01:31:16.900 | And then you can try and apply those either separately

01:31:19.900 | or maybe combine them in some way

01:31:21.660 | that's useful for your goals.

01:31:23.220 | There are a couple of key elements

01:31:24.740 | that are essential for building a safe and effective

01:31:27.580 | range of motion increasing program

01:31:30.600 | that arrived to us both through the peer reviewed research

01:31:33.240 | and admittedly from people that have been involved

01:31:35.980 | in teaching and training range of motion

01:31:38.500 | for a very long period of time.

01:31:40.340 | Some of you may be familiar

01:31:41.580 | with the so-called Anderson method.

01:31:43.200 | It's been around for a long time.

01:31:45.160 | I actually have never met Anderson.

01:31:46.700 | I don't, I should know this.

01:31:48.020 | I don't even know if he's still alive.

01:31:49.280 | I hope he's still alive.

01:31:50.480 | But in any event, there are a lot of different features

01:31:53.060 | to the Anderson and other protocols.

01:31:55.160 | But one of the aspects of the Anderson protocol

01:31:57.720 | that I think is highly relevant,

01:31:59.300 | in fact, I know is relevant to the peer reviewed research

01:32:01.500 | that we're going to talk about in a few moments

01:32:03.580 | is this notion of pushing through pain

01:32:06.820 | and how active or how passive to be about static stretching.

01:32:10.740 | Now this is somewhat subjective, right?

01:32:12.780 | If you think about getting into a stretch,

01:32:15.700 | again, we'll just use the hamstrings for example.

01:32:17.540 | So you're either reaching for your toes while seated

01:32:21.480 | or maybe you're using a strap

01:32:23.820 | and you're raising your foot overhead while lying down,

01:32:27.100 | or maybe you're doing a toe touch type exercise.

01:32:31.220 | How far should you reach?

01:32:34.020 | Where is the end range of motion?

01:32:36.220 | Should you bounce?

01:32:37.060 | Should you not bounce?

01:32:37.880 | We're going to talk a little bit more

01:32:38.720 | about that in a moment.

01:32:40.020 | But Anderson has an interesting idea and principle

01:32:42.660 | which is thread through a lot of his teachings

01:32:44.980 | that I think are very much in keeping with the study

01:32:47.860 | that I'm about to describe next,

01:32:49.660 | where he emphasizes to yes,

01:32:53.160 | to stretch to the end of the range of motion,

01:32:56.520 | but not to focus so much on where that range of motion

01:32:59.340 | happens to be that day.

01:33:01.320 | So for instance, not thinking,

01:33:03.800 | oh, I can always touch my toes, for instance,

01:33:06.880 | and therefore that's the starting place

01:33:09.240 | for my flexibility training today,

01:33:11.820 | but rather to take the entirety of your system

01:33:15.120 | into account each day and understand that,

01:33:17.060 | okay, provided you're warmed up appropriately,

01:33:19.780 | that you're now going to stretch your hamstrings,

01:33:21.420 | for instance, and you're going to reach down for your toes,

01:33:24.500 | but that your range of motion might be adjusted that day

01:33:27.580 | by way of tension and stress,

01:33:29.660 | or by way of ambient temperature in the room.

01:33:31.900 | And to basically define the end range of motion

01:33:34.660 | as the place where you can feel the stretch

01:33:37.780 | in the relevant muscle groups.

01:33:39.380 | I think this is important because unlike resistance training

01:33:43.140 | or cardiovascular training,

01:33:44.780 | where we can measure distance traveled over time

01:33:47.400 | in the case of cardiovascular training,

01:33:48.860 | or how much weight is on the bar

01:33:50.620 | and count repetitions, et cetera,

01:33:52.860 | with range of motion training,

01:33:54.840 | of course, range of motion is the feature

01:33:56.980 | that we're interested in,

01:33:58.200 | but there is likely to be a lot of variation from day to day

01:34:02.220 | based on a number of different internal and external factors.

01:34:05.500 | And so the Anderson method is really about

01:34:07.820 | getting into static and other forms of stretching.

01:34:10.500 | I think today we've mainly been focusing on static stretching

01:34:12.880 | and holding the end range of motion,

01:34:15.300 | but really paying attention to the feel of the stretch

01:34:18.140 | and the muscles involved.

01:34:19.460 | And there are parallels in resistance

01:34:21.520 | in cardiovascular training too, I realize, right?

01:34:23.820 | In the case of trying to build hypertrophy,

01:34:26.220 | or I should say improve hypertrophy muscle size,

01:34:29.160 | oftentimes the best advice that one can give

01:34:32.180 | is to don't try to lift weights,

01:34:33.940 | but rather to challenge muscles.

01:34:35.400 | Now, of course, you need to provide adequate loads

01:34:37.240 | in order to get hypertrophy,

01:34:38.760 | but when you're training purely for strength,

01:34:40.400 | it's about moving weights.

01:34:42.480 | When you're training purely for hypertrophy

01:34:44.160 | or mainly for hypertrophy,

01:34:45.260 | it's really about challenging muscles

01:34:47.260 | using weights or other forms of resistance.

01:34:49.500 | And similarly, and in keeping with this Anderson method,

01:34:54.040 | when trying to build limb range of motion,

01:34:57.260 | doing static stretching at a place where it's difficult,

01:35:00.740 | but that you can experience the stretch of the muscle

01:35:03.780 | cognitively, consciously,

01:35:05.700 | being able to focus on the muscles and their stretch

01:35:08.800 | is at least as useful as is evaluating

01:35:12.640 | the current range of motion you're able to achieve.

01:35:14.660 | So what does this mean?

01:35:15.500 | This means feel the muscles as you stretch them,

01:35:17.400 | don't just go through the motions.

01:35:18.720 | And this means don't get so attached

01:35:21.340 | to being able to always achieve, for instance,

01:35:23.680 | a stretch of a given distance within a given session.

01:35:26.880 | You might actually find that by just finding the place

01:35:30.240 | where you can't get much further

01:35:32.100 | and holding the static stretch there,

01:35:34.240 | that on the second and third set

01:35:35.680 | that you happen to be doing that day,

01:35:36.820 | that your range of motion will be increased considerably.

01:35:40.100 | Maybe not, but very likely, yes, you will.

01:35:42.580 | And of course, evaluating range of motion over time

01:35:46.180 | is the key parameter because that's the goal

01:35:48.460 | of all this type of work.

01:35:49.640 | Now, along these lines,

01:35:52.900 | there is this variable that we've mentioned a few times

01:35:55.220 | of passive versus active stretching.

01:35:57.340 | And there's this even more nebulous variable,

01:36:00.340 | this even more kind of subjective thing

01:36:02.120 | of how much effort to put into it.

01:36:05.500 | Should you push into the stretch?

01:36:07.620 | Do you even want to bounce a tiny bit?

01:36:09.500 | Would you want to reach into that end point

01:36:12.600 | and try and extend it within a given set and session?

01:36:15.960 | And for that reason, I was excited to find this paper

01:36:20.520 | entitled "A Comparison of Two Stretching Modalities

01:36:22.820 | on Lower Limb Range of Motion Measurements

01:36:24.900 | in Recreational Dancers."

01:36:26.900 | It happens to be done in recreational dancers.

01:36:28.640 | It's a six-week intervention program

01:36:30.680 | that compared low-intensity stretching,

01:36:32.640 | which they call micro-stretching.

01:36:34.900 | They used a capital M.

01:36:35.940 | So I don't know if that means that it's proprietary,

01:36:37.940 | although I didn't see evidence of a conflict of interest,

01:36:41.640 | but they call it micro-stretching.

01:36:43.420 | But to be very clear,

01:36:46.460 | micro-stretching in the case of this manuscript

01:36:48.740 | is low-intensity stretching.

01:36:50.820 | And they compared that with moderate-intensity

01:36:52.940 | static stretching on an active and passive ranges of motion.

01:36:56.900 | Okay, so there are a lot of different variables are here,

01:36:58.900 | but I'll just highlight a few of the things

01:37:01.420 | that are really most relevant to us.

01:37:03.120 | And I'll give you the takeaway at the outset

01:37:05.060 | and then return to it at the end

01:37:06.500 | so that if I lose any of your attention

01:37:09.420 | in the next couple of minutes,

01:37:10.380 | at least you have that key takeaway.

01:37:14.100 | Basically, what they found was that

01:37:15.580 | a six-week training program

01:37:17.020 | using very low-intensity stretching

01:37:19.780 | had a greater positive effect on lower limb range of motion

01:37:22.900 | than did moderate-intensity static stretching.

01:37:26.040 | I find that incredibly interesting.

01:37:27.440 | So very low intensity,

01:37:28.800 | and we'll define what that means in a moment.

01:37:31.980 | Here, I'm quoting them.

01:37:33.560 | "The most interesting aspect of the study was

01:37:35.700 | the greater increase in active range of motion

01:37:37.760 | compared to passive range of motion

01:37:39.360 | by the micro-stretching group."

01:37:40.720 | So this relates to what we were just talking about

01:37:42.640 | a few moments ago as it relates to the Anderson method,

01:37:45.780 | which is that very low-intensity stretching,

01:37:49.960 | meaning effort that feels not painful,

01:37:53.680 | and in fact, might even feel easy

01:37:56.860 | or at least not straining

01:37:59.440 | to exceed a given range of motion,

01:38:02.700 | turns out to not just be as effective,

01:38:04.920 | but more effective than moderate-intensity stretching.

01:38:08.640 | So what is low-intensity static stretching?

01:38:11.080 | Well, they define this as the stretches were completed

01:38:13.640 | at an intensity of 30 to 40%,

01:38:17.320 | where 100% equals the point of pain, right?

01:38:20.840 | So 30 to 40% in these individuals,

01:38:24.440 | and again, I'm paraphrasing,

01:38:25.640 | induced a relaxed state within the individual

01:38:28.600 | and the specific muscle,

01:38:29.680 | and here they were holding these static stretches,

01:38:31.680 | I should mention, for one minute, not 30 seconds.

01:38:35.340 | Now, the control group was doing

01:38:37.520 | the exact same overall protocol,

01:38:39.560 | so daily stretching for six weeks, the same exercises,

01:38:44.300 | holding each set for 60 seconds,

01:38:47.120 | but we're using an intensity of stretch of 80%,

01:38:51.320 | where, again, 100 represents the point of pain

01:38:54.840 | or the point where the person would want to stop stretching.

01:38:58.240 | I find these data incredibly interesting

01:38:59.900 | for I think what ought to be obvious reasons.

01:39:02.480 | If you're going to embark on a flexibility

01:39:05.360 | and stretching training program,

01:39:07.760 | you don't need to push to the point of pain.

01:39:09.880 | In fact, it seems that even just approaching

01:39:12.580 | the point of pain is going to be less effective

01:39:15.080 | than operating at this 30 to 40% of intensity

01:39:20.080 | prior to reaching that pain threshold,

01:39:21.960 | the pain threshold being 100%.

01:39:23.600 | Now, of course, this is pretty subjective,

01:39:25.080 | but I think all of us should be able to register

01:39:27.920 | within ourselves as to whether a given range of motion

01:39:31.560 | or extending a given range of motion

01:39:32.960 | brings us to that threshold of pain or near pain.

01:39:35.720 | And according to this study, at least,

01:39:37.680 | operating or performing stretching

01:39:41.600 | at an intensity that's quite low, that's very relaxing,

01:39:44.720 | turns out to be more beneficial

01:39:46.920 | in increasing range of motion than is doing exercises

01:39:51.440 | aimed at increasing range of motion at a higher intensity.

01:39:54.360 | Okay, so lower intensity stretching,

01:39:56.760 | I should say lower intensity static stretching

01:39:59.340 | appears to be the most beneficial way to approach stretching.

01:40:02.360 | And I think that's a relief probably to many of us

01:40:05.600 | because it also suggests that the injury risk

01:40:08.720 | is going to be lower than if one were pushing

01:40:10.760 | into the pain zone, so to speak.

01:40:12.960 | The authors offer a number of different explanations

01:40:15.160 | as to why this microstretching approach

01:40:17.900 | might be more effective.

01:40:19.120 | Here, I'm paraphrasing from their discussion

01:40:22.440 | where they mentioned that it could be hypothesized

01:40:25.760 | that they had improved reciprocal inhibition

01:40:28.640 | within the hamstring muscle group.

01:40:29.840 | So this gets right back to the sorts of neural mechanisms

01:40:31.960 | that we talked about before,

01:40:32.900 | that somehow by doing this low intensity stretching,

01:40:35.760 | that they were able to access some of those spindle

01:40:37.720 | and GTO type mechanisms that we were referring to earlier

01:40:41.000 | and the inhibition of hamstring and quadricep stretches.

01:40:44.600 | They also offer a number of different ideas

01:40:47.120 | about how this could shift the activation

01:40:50.640 | of the so-called sympathetic,

01:40:51.840 | remember the kind of stress division of our nervous system,

01:40:55.520 | and to reduce that relative to activation

01:40:59.620 | of the parasympathetic arm of the nervous system.

01:41:01.940 | I confess they have a couple of arguments

01:41:03.640 | around sympathetic, parasympathetic

01:41:05.300 | that are somewhat convoluted.

01:41:06.900 | I will just, in fairness to the neuroscience

01:41:10.900 | on those systems, I wouldn't suggest putting too much weight

01:41:15.260 | on their arguments about sympathetic and parasympathetic.

01:41:17.980 | To my mind, they didn't really hold much water,

01:41:20.320 | but here I'm not trying to be disparaging

01:41:22.340 | of the overall work, which I think is really quite sound,

01:41:24.960 | which is that low intensity so-called microstretching

01:41:28.480 | is going to be the most effective way

01:41:30.360 | to increase limb range of movement over time.

01:41:33.200 | I want to just briefly return to this idea

01:41:35.240 | of whether or not to do ballistic or static stretching

01:41:37.880 | before some sort of skill training or weight training

01:41:41.920 | or any kind of sport

01:41:43.720 | or even cardiovascular exercise like running.

01:41:46.300 | Again, the data are really split out there.

01:41:49.240 | There are even folks who suggest

01:41:50.920 | that doing any kind of stretching prior to running

01:41:53.460 | is going to lower running efficiency.

01:41:55.240 | It's going to require essentially more work

01:41:57.120 | and more oxygen uptake at a given speed

01:41:59.180 | for a variety of reasons.

01:42:01.180 | And runners and that community argue about this endlessly.

01:42:04.660 | There are papers in both sides in both directions.

01:42:06.760 | I'm sure I'll hear about some of this in the comments.

01:42:09.040 | I'm not really going to take a stance on this

01:42:10.580 | as a consequence because the data are all over the place.

01:42:14.560 | However, I think there's a general logic

01:42:16.900 | that we can apply in here.

01:42:17.960 | I'm borrowing from some conversations

01:42:20.400 | and some information put out there by Dr. Andy Galpin,

01:42:23.200 | who I think is, of course, both an expert

01:42:25.940 | and thinks about these things

01:42:26.780 | in a really sound and flexible way, no pun intended.

01:42:30.500 | There are instances, for example,

01:42:34.920 | where an individual might want to do some static stretching

01:42:37.700 | to increase limb range of motion

01:42:39.520 | prior to doing weight training,

01:42:41.140 | even if it's going to inhibit that person's ability

01:42:44.660 | to lift as much weight.

01:42:46.300 | Why would you want to do that?

01:42:47.340 | Well, for instance, if somebody has a tightness

01:42:50.160 | or a limitation in their neuromuscular connective tissue

01:42:53.140 | system someplace in their body and system

01:42:56.600 | that prevents them from using proper form

01:43:00.000 | that they can overcome by doing some static stretching,

01:43:03.720 | well, that would be a great idea, as Dr. Galpin points out.

01:43:07.600 | Or for instance, if proper stability within the movement

01:43:11.480 | requires increasing limb range of motion in some way,

01:43:14.540 | well, then compromising the use of greater loads

01:43:18.720 | could be greatly offset by doing some static stretching

01:43:22.000 | to improve, say, hamstring flexibility

01:43:23.840 | or another muscle group flexibility.

01:43:25.560 | So we can't always think about just what's going to allow us

01:43:28.320 | or inhibit us from using the maximum amount of weight

01:43:30.960 | or from running as far as we want to run

01:43:33.680 | as fast as we want to run.

01:43:35.240 | There are instances where people are trying

01:43:36.880 | to overcome injuries, where they're trying to come back

01:43:39.920 | from a reparative surgery or something of that sort,

01:43:42.840 | coming back from a layoff,

01:43:44.040 | where some additional static stretching prior

01:43:47.560 | to cardiovascular weight training or skill training

01:43:49.920 | or sport of some kind is going to be useful

01:43:52.640 | because it's going to put us in a position

01:43:54.600 | of greater safety and confidence and performance overall,

01:43:58.180 | even if it's adjusting down our speed

01:44:00.680 | or the total amount of loads that we use.

01:44:02.880 | So it's you that needs to consider whether or not,

01:44:06.240 | for you and within a given training session,

01:44:09.420 | you want to do static training,

01:44:12.160 | I should say static stretching range of motion training,

01:44:15.000 | prior to or after that training session.

01:44:18.560 | And similarly, there are a lot of data points

01:44:22.400 | in the fact that doing some dynamic

01:44:24.120 | or even ballistic stretching prior to skill training

01:44:27.400 | or cardiovascular weight training can be beneficial

01:44:29.960 | in part to warm up the relevant neural circuits,

01:44:32.360 | joints and connective tissue and muscles,

01:44:35.000 | and as well to perhaps improve range of motion

01:44:38.760 | or ability to perform those movements more accurately

01:44:42.120 | with more stability and therefore with more confidence.

01:44:45.160 | And while Dr. Andy Galpin would never name

01:44:47.560 | any protocol after himself, he's far too humble to do that.

01:44:50.720 | I've named a couple of protocols after him,

01:44:52.780 | particularly the Galpin equation for hydration,

01:44:55.640 | because he was willing to stick his neck out there

01:44:58.000 | and put down some specific numbers that people could follow

01:45:02.280 | in order to ensure proper hydration during training.

01:45:04.900 | You can look up the Galpin equation elsewhere,

01:45:07.320 | you can just Google it or look elsewhere, you'll find it.

01:45:10.680 | And Dr. Galpin has also been very thoughtful and generous,

01:45:15.280 | and I think very accurate in offering a kind of a general

01:45:19.000 | organizational logic for how to think about the goals

01:45:22.880 | of a particular training session and thereby to decide

01:45:27.420 | whether or not you're going to do ballistic

01:45:28.680 | or static stretching and so on and so forth.

01:45:31.040 | So we can refer to this general approach

01:45:33.720 | as Galpinian, Galpinian, is that right?

01:45:37.480 | Galpinian logic, Galpinian logic.

01:45:41.560 | Thus far, we've been talking about stretching

01:45:43.220 | for sake of increasing limb flexibility and range of motion,

01:45:46.500 | but there are other reasons perhaps

01:45:49.520 | to embark on a stretching protocol

01:45:52.120 | that include both our ability to relax

01:45:55.760 | and access deep relaxation quickly,

01:45:58.120 | as well as even to reduce inflammation

01:46:01.660 | and perhaps even combat certain forms of cancer.

01:46:04.600 | And if that sounds really far-fetched,

01:46:07.380 | I want to emphasize that the study I'm about to share

01:46:09.380 | with you in a moment was actually carried out

01:46:11.400 | by one of the directors of a division

01:46:14.660 | of the National Institutes of Health.

01:46:17.400 | And this was the work of Helene Langevin,

01:46:21.100 | who's a medical doctor, has done really important work

01:46:24.440 | on the mechanisms underlying things like acupuncture

01:46:29.980 | and has approached all that

01:46:31.260 | from a very mechanistic viewpoint, right?

01:46:34.220 | So not looking just at the effects of acupuncture,

01:46:36.420 | but really trying to understand what sorts of cytokines,

01:46:39.400 | inflammatory molecules and pathways are activated,

01:46:43.000 | what sorts of neural mechanisms get engaged

01:46:46.000 | by things like acupuncture that impinges

01:46:49.300 | on the fascial tissues and so forth.

01:46:52.160 | And Dr. Langevin is currently a director

01:46:54.320 | of the National Institutes of Complementary Health

01:46:57.160 | and Medicine at the National Institutes of Health.

01:47:00.680 | So this is a major division supported by tax dollars

01:47:03.680 | that support systematic mechanistic exploration

01:47:07.160 | of things like respiration, meditation, yoga, acupuncture.

01:47:11.400 | So this is serious science applied to protocols

01:47:14.260 | and approaches that have been used for some period of time,

01:47:16.080 | but really aimed at trying to understand

01:47:17.740 | what would the best protocols be to evolve new protocols.

01:47:21.660 | So there's a really interesting study done in animal models,

01:47:25.280 | but I think it's a powerful enough result

01:47:27.480 | that I think we all should pay attention to it.

01:47:29.620 | The title of this paper, and again,

01:47:31.040 | the last author is Dr. Langevin herself,

01:47:33.720 | is stretching reduces tumor growth in a mouse

01:47:37.320 | breast cancer model.

01:47:38.600 | And yes, you can get mice to stretch.

01:47:40.580 | It turns out that if you gently lift up mice by their tail

01:47:44.040 | and they'll hold onto their cage,

01:47:45.020 | there's a way in which you can mechanically stretch them

01:47:47.400 | in a way that doesn't harm them.

01:47:48.860 | First, I should mention that Dr. Langevin and others

01:47:51.240 | have shown that just a brief whole body stretch

01:47:54.080 | of that sort induces an increase in activation

01:47:58.100 | of the parasympathetic arm of the autonomic nervous system.

01:48:01.900 | Again, not arm limb arm, but the aspect

01:48:04.420 | of the autonomic nervous system that creates a whole body,

01:48:08.140 | whole nervous system shift toward more relaxation.

01:48:11.840 | So yes, indeed, stretching induces relaxation

01:48:16.140 | at a systemic level, not just at a local level.

01:48:19.380 | And I think that's important.

01:48:21.100 | Probably not surprising to those of you

01:48:22.640 | that use stretching regularly,

01:48:24.260 | but yes, it does indeed relax us.

01:48:26.340 | Yes, you can do this in mice and see that in mice as well.

01:48:29.580 | Here's what they did for this current study,

01:48:31.940 | or I should say this was a study published in 2018

01:48:35.660 | in Scientific Reports.

01:48:37.020 | They write, "Recent studies have shown

01:48:40.780 | "that gentle daily stretching for 10 minutes

01:48:42.500 | "can reduce local connective tissue inflammation

01:48:44.600 | "and fibrosis."

01:48:45.440 | Now that's local tissue inflammation and fibrosis

01:48:49.700 | as well we now know as systemic inflammation

01:48:53.760 | and can induce relaxation systemically.

01:48:57.740 | In this case, they focused on mice, not humans.

01:49:00.840 | And mice were randomized to a stretch

01:49:02.640 | versus no stretch condition and were treated

01:49:05.220 | for 10 minutes once a day for four weeks.

01:49:08.420 | So it's 10 minutes of this passive whole body stretching

01:49:11.700 | a day for four weeks.

01:49:14.680 | What's remarkable, I mean, just I have to say

01:49:17.120 | is just striking is that tumor volume in these mice,

01:49:20.440 | they were able to induce tumors in these mice

01:49:22.100 | and the tumor volume at the end point

01:49:24.100 | was 52% smaller in the stretch group.

01:49:27.460 | Compared to the no stretch group.

01:49:29.280 | This is a highly significant effect.

01:49:31.560 | And they point out in the absence of any other treatment.

01:49:34.940 | And they explored whether or not cytotoxic immune responses

01:49:37.700 | were activated and a number of other features.

01:49:40.500 | They weren't able to get too deeply

01:49:41.740 | into the underlying mechanisms,

01:49:43.900 | but this is pretty remarkable.

01:49:45.540 | Even three weeks into this stretching protocol,

01:49:47.980 | this daily stretching protocol for these mice,

01:49:49.800 | tumor volume was reduced.

01:49:51.020 | I mean, by, you know, it's almost halved.

01:49:54.040 | This is pretty incredible.

01:49:55.620 | So they have these measures of tumor volume

01:49:57.620 | and the only difference in the way these animals

01:50:01.340 | were treated and handled was the introduction

01:50:04.580 | of this daily stretch.

01:50:06.220 | I find this result to be of course limited

01:50:09.700 | and to the extent that it's done in an animal model,

01:50:12.140 | not in humans, we have to point that out.

01:50:14.100 | But as they point out in their discussion,

01:50:16.200 | our results demonstrate a 52% reduction

01:50:18.300 | in mammary tumor growth over one month

01:50:20.380 | in mice undergoing stretching for 10 minutes a day

01:50:22.560 | without any other form of therapy.

01:50:24.660 | Do they think that stretching itself

01:50:26.980 | is changing the tumor size?

01:50:28.500 | No.

01:50:29.340 | In fact, they raised the possibility that stretching

01:50:31.820 | because of its impact on the fascia

01:50:33.700 | might even create micro environments

01:50:35.380 | that are more permissive for tumor growth

01:50:37.720 | in certain instances.

01:50:38.820 | So they're careful to emphasize

01:50:41.260 | what I also believe to be the case,

01:50:42.880 | which is that it's unlikely that the stretching itself

01:50:45.020 | was directly acting to reduce tumor size,

01:50:47.560 | but rather that there's this possible link

01:50:50.320 | between inflammation and immune exhaustion mechanisms

01:50:53.580 | that if you can periodically relax a nervous system,

01:50:58.020 | here through stretching,

01:50:59.260 | that it can affect certain pathways

01:51:02.300 | related to the immune system

01:51:03.400 | that would allow the immune system to combat tumor growth

01:51:06.540 | to a significant degree.

01:51:07.800 | So again, even though this is a study in mice,

01:51:10.060 | it argues that relaxation induced by stretching

01:51:12.860 | can have a powerful influence on mammary tumor growth.

01:51:15.540 | Again, a huge effect carried out by one of the premier labs

01:51:20.860 | and individuals who do this sort of work

01:51:23.980 | and think about this sort of thing.

01:51:25.060 | And of course, I want to point out,

01:51:26.040 | it wasn't just Dr. Langevin that did this study.

01:51:28.120 | There are a number of co-authors on the study.

01:51:29.640 | We'll provide a link to the co-authors.

01:51:32.140 | Excuse me, we will provide a link to the study

01:51:34.300 | so that you can peruse it in more detail if you like.

01:51:37.100 | Now, as a related and somewhat final point,

01:51:40.460 | I'd like to return to this idea and this place,

01:51:43.500 | this real estate within our brain

01:51:45.480 | that we call the insular cortex, the insula.

01:51:48.140 | As you recall, way back at the beginning

01:51:50.560 | of this episode, we were talking about

01:51:51.500 | the von Economo neurons, that Constantine von Economo,

01:51:54.700 | the Austrian scientist discovered.

01:51:58.100 | And the fact that we are able to make

01:52:01.260 | and perform interpretations of our internal landscape pain,

01:52:05.540 | our dedication to a practice.

01:52:07.980 | For instance, whether or not we are in pain

01:52:10.840 | because it's a practice that we are doing intentionally

01:52:14.100 | and want to improve ourselves,

01:52:15.520 | or whether or not it's pain that's arriving

01:52:17.380 | through some externally imposed demands or situations.

01:52:20.880 | Well, the insula is handling all that.

01:52:23.400 | And fortunately, there's a wonderful paper

01:52:26.120 | that was published, it was a few years ago now

01:52:28.840 | in the journal Cerebral Cortex, which is a fine journal.

01:52:31.380 | This is the year 2014 entitled Insular Cortex Mediates

01:52:34.740 | Increased Pain Tolerance in Yoga Practitioners.

01:52:37.360 | I'll tell you why I like this study.

01:52:39.200 | I'm personally not a practitioner of yoga.

01:52:41.120 | I've taken a few yoga classes over the years.

01:52:42.940 | I've done some of the hot yoga classes.

01:52:45.860 | Those rooms can get really, really warm, I confess.

01:52:49.440 | And I've done the kind of standard yoga every now and again.

01:52:51.840 | It's not something that I've kept up regularly.

01:52:54.180 | This study explored the effects on brain structure volume

01:53:00.180 | in yoga practitioners.

01:53:03.680 | And for those of you out there that are aficionados in yoga,

01:53:06.680 | they pulled subjects from having backgrounds in the,

01:53:11.400 | here I'm probably going to mispronounce

01:53:12.720 | these different things and forgive me,

01:53:14.440 | the vinyasa yogas, the ashtanga yogas,

01:53:17.020 | younger yogas, the sunanda yogas.

01:53:19.300 | Okay, so some people were new to these practices.

01:53:21.580 | Some were experienced.

01:53:24.060 | The important takeaways were that

01:53:26.240 | they took these yoga practitioners

01:53:28.160 | and they didn't explore their brain structure

01:53:30.260 | in the context of yoga itself.

01:53:31.560 | They looked at things like pain tolerance.

01:53:34.440 | So they used thermal stimulation.

01:53:36.460 | Basically, they put people into conditions

01:53:37.940 | where they gave them very hot or very cold stimuli

01:53:40.360 | and compared those yoga practitioners

01:53:43.120 | of varying levels of yoga experience

01:53:44.940 | to those that had no experience with yoga,

01:53:47.240 | so-called controls.

01:53:48.400 | And they found some really interesting things.

01:53:51.080 | I got a lot of data on this paper,

01:53:52.760 | but here's something I'd like to highlight.

01:53:55.760 | The pain tolerance of yoga practitioners

01:53:59.220 | was double or more to that of non-yoga practitioners,

01:54:04.220 | even for those that weren't doing

01:54:05.580 | the so-called hot yoga, right?

01:54:07.240 | They also found that pain tolerance was significantly greater

01:54:10.560 | both for heat pain and for cold pain.

01:54:13.280 | They also found significant increases in insular,

01:54:17.800 | again, the insula, this brain region, gray matter volume.

01:54:21.880 | Typically, when we talk about gray matter,

01:54:23.400 | we're talking about the so-called cell bodies,

01:54:25.360 | the location in neurons where the genome is housed

01:54:29.920 | and where all the housekeeping stuff is there.

01:54:33.080 | And then white matter volume tends to be the axons,

01:54:36.000 | the wires, because they're in sheaths

01:54:37.440 | with this stuff that appears white in MRIs

01:54:40.200 | and indeed is white under the microscope

01:54:42.000 | and indeed is white.

01:54:42.840 | It's actually lipid, which is myelin.

01:54:44.700 | So increased gray matter volume of the insula

01:54:48.260 | is a significant finding because what it suggests

01:54:51.700 | is that people that are doing yoga

01:54:53.560 | have an increased volume of these areas of the brain.

01:54:56.480 | They're associated with interoceptive awareness

01:54:59.080 | and for being able to make judgments about pain

01:55:02.080 | and why one is experiencing pain,

01:55:03.920 | not just to lean away from pain,

01:55:05.260 | but to utilize or leverage or even overcome pain.

01:55:08.660 | So there are many studies of yoga and meditation out there,

01:55:12.940 | few that have as much mechanistic detail as this one.

01:55:15.940 | And in fact, there's a beautiful figure,

01:55:18.380 | figure three in this paper,

01:55:19.860 | that shows that the gray matter volume

01:55:21.700 | of this particular brain region scales

01:55:24.460 | in an almost linear way with the duration of yoga practice

01:55:28.300 | that somebody has been taking on in years.

01:55:29.980 | So people that had, they had a few subjects

01:55:32.320 | that have up to 15 or 16 years of yoga practice

01:55:35.340 | had much larger left insular gray matter volume,

01:55:39.260 | bigger brain areas associated with these abilities.

01:55:42.660 | And I find this interesting

01:55:44.180 | because there are a lot of activities out there

01:55:46.860 | that don't create these kinds of changes in brain volume,

01:55:50.540 | especially within the insula.

01:55:52.060 | So it appears that it's not just the performance

01:55:54.380 | of the yogic movements, but the overcoming

01:55:57.000 | or the kind of pushing into the end ranges of motion

01:55:59.860 | and to push through discomfort to some extent.

01:56:03.460 | Of course, we want people doing that in a healthy safe way,

01:56:06.700 | but that's allows yoga practitioners

01:56:08.660 | to build up the structure and function of these brain areas

01:56:13.180 | that allow them to cope with pain better

01:56:15.340 | than other individuals and to cope with other kinds

01:56:17.980 | of interoceptive challenges, if you will,

01:56:21.260 | not just pain, but cold, not just pain,

01:56:24.620 | but discomfort of being in a particular position

01:56:27.220 | to do that.

01:56:28.060 | And again, we wouldn't want people placing themselves

01:56:30.260 | into a compromised position literally that would harm them,

01:56:33.900 | especially given that earlier we heard that microstretching

01:56:37.540 | of the kind of non-painful sort, low intensity sort

01:56:39.820 | is actually going to be more effective

01:56:41.220 | for increasing end range of motion.

01:56:42.960 | But this study really emphasizes the extent

01:56:45.020 | to which practitioners of yoga don't just learn movements,

01:56:49.960 | they learn how to control their nervous system in ways

01:56:52.980 | that really reshapes their relationship to pain,

01:56:56.960 | to flexibility, and to the kinds of things

01:56:59.900 | that the neuromuscular system was designed to do.

01:57:03.180 | And as a final point, there's a beautiful graph

01:57:06.820 | in this paper, beautiful, I think,

01:57:08.000 | because it explores some of the more subjective dimensions

01:57:11.060 | of yoga and insular function, which is a,

01:57:15.980 | here I'll read it out in the nerdy form,

01:57:18.560 | and then I'll explain what it means.

01:57:19.940 | This is a frequency histogram of categories

01:57:22.340 | of mental strategies used by yogis versus controls

01:57:25.700 | during the cold pain tolerance task.

01:57:27.740 | What they're describing here and showing is quantitatively

01:57:32.740 | how people are conceptualizing cold pain

01:57:36.220 | in order to get through it.

01:57:37.860 | And the different categories are,

01:57:39.500 | for instance, distraction, right?

01:57:41.640 | Some people just choose to distract themselves

01:57:44.140 | from pain or to attempt to.

01:57:45.300 | Other people will try to ignore it.

01:57:46.900 | It's a lot like distraction, but nonetheless,

01:57:50.940 | to engage in a negative emotion,

01:57:53.100 | sort of like, I'm going to dig,

01:57:54.680 | I'm going to be in resistance to this.

01:57:57.600 | Control subjects tended to use those approaches,

01:58:00.740 | whereas practitioners of yoga tended to use other sorts

01:58:04.520 | of subjective approaches, like positive imagery,

01:58:07.540 | to some extent, the ability to relax

01:58:10.560 | despite the extreme cold, the ability to quote unquote,

01:58:15.280 | accept, like this is just happening

01:58:17.380 | despite the extreme cold,

01:58:18.800 | to observe, to third person themselves.

01:58:21.240 | And the greatest effect of course was to breathe,

01:58:24.940 | to focus on their respiration

01:58:27.120 | as a way to deal with this challenge, this cold challenge.

01:58:31.380 | Now, all of that is our subjective data,

01:58:34.260 | but I want to remind you that the practitioners of yoga

01:58:38.440 | are not just using entirely different mental strategies,

01:58:41.320 | but they are far more effective at dealing with pain.

01:58:44.960 | Their pain tolerance is much higher as evidenced

01:58:48.480 | by the other data in the previous graphs in the paper.

01:58:51.360 | So while this podcast episode is most certainly

01:58:54.360 | not about yoga per se,

01:58:55.960 | it's about flexibility and stretching.

01:58:58.580 | Flexibility and stretching are elements

01:59:00.240 | within yoga practices.

01:59:02.360 | And of course, yoga practices involve breathing

01:59:04.720 | and mental work and a lot of other things,

01:59:07.460 | balance, et cetera.

01:59:08.400 | It's a vast landscape as many of you know.

01:59:11.220 | But I think that if ever there was a manuscript

01:59:14.400 | that pointed to the utility of something like yoga

01:59:17.780 | for sake of tapping into a particular set of brain circuits

01:59:21.940 | and mechanisms that could wick out

01:59:24.200 | into multiple dimensions of life,

01:59:26.480 | so day-to-day life, stress,

01:59:29.440 | challenges in dealing with all sorts of external stressors,

01:59:32.480 | career-related, family-related, relationally, et cetera,

01:59:37.460 | excuse me, but as well for increasing range of motion,

01:59:41.820 | for increasing flexibility.

01:59:43.320 | So if ever there was a practice that one could embark on

01:59:46.740 | that would not only increase flexibility

01:59:48.920 | and limb range of motion,

01:59:49.940 | but would also allow one to cultivate

01:59:52.280 | some improved mental functioning

01:59:54.300 | as it relates to pain tolerance

01:59:55.780 | and other features of stress management

01:59:58.160 | that no doubt wick out into other areas of life,

02:00:01.160 | appears that yoga is a quite useful practice.

02:00:04.320 | And so for those of you that are interested

02:00:06.060 | in increasing limb range of motion,

02:00:07.580 | and you're already a practitioner of yoga, great.

02:00:10.040 | I can imagine that someday there'll be another study

02:00:12.460 | like this one, and you'll be in that 10 or 15

02:00:15.880 | to 16-year practitioner graph.

02:00:18.520 | You'll be that dot way out on the far end of the graph

02:00:21.780 | that shows that your insula is that much bigger

02:00:23.720 | than the rest of ours.

02:00:25.000 | And therefore, your internal awareness and pain thresholds

02:00:27.960 | and stress management will be that much better.

02:00:30.140 | But of course, yoga isn't the only way

02:00:32.880 | to increase limb range of motion and flexibility.

02:00:35.740 | Up until now, we've described a number of different ways

02:00:39.120 | to do that, and we've arrived at some general themes

02:00:41.520 | and protocols.

02:00:42.360 | Again, those themes and protocols will be distilled

02:00:44.980 | into some specific and precise list in our neural network

02:00:48.720 | newsletter, but we can revisit a couple of them now

02:00:51.340 | just in summary and synthesis.

02:00:54.200 | Static stretching appears to be at least among

02:00:56.700 | the more useful forms of stretching.

02:00:58.400 | So low or zero momentum stretching,

02:01:01.200 | typically at end range of motion.

02:01:03.800 | I love this concept of micro stretching,

02:01:07.060 | even though it's just a couple of studies

02:01:08.840 | that have addressed whether or not high-intensity

02:01:11.120 | or low-intensity static stretch holds are more beneficial.

02:01:14.260 | The idea and indeed the data that low intensity,

02:01:18.160 | so 30 to 40% of what one would consider painful

02:01:23.160 | appears to be more effective than 80% of that threshold.

02:01:27.360 | Find that incredibly interesting.

02:01:28.720 | And then there's this idea of frequency.

02:01:30.960 | It really does appear that getting at least five minutes

02:01:35.120 | per week total of stretching for a given muscle group

02:01:37.880 | is important for creating meaningful lasting changes

02:01:41.160 | in limb range of motion.

02:01:42.720 | And that is best achieved by five day a week

02:01:46.560 | or six day a week or even seven day a week protocols,

02:01:49.280 | but those can be very short protocols limited to say,

02:01:52.580 | three sets of 30, maybe in 45 or 60 seconds of static hold.

02:01:57.500 | Although 30 seconds seems to be a key threshold there

02:02:01.500 | that can get you maximum benefit.

02:02:03.720 | There is no need to do full 60 second holds

02:02:05.720 | unless you're doing fewer total sessions per week.

02:02:08.400 | And of course, to always warm up or to arrive

02:02:11.340 | at the stretching session warm.

02:02:13.000 | And then of course, there are the other forms of stretching

02:02:15.280 | that we touched upon a bit, things like PNF.

02:02:18.300 | And we talked about why PNF works.

02:02:20.320 | Things like the spindle and the Golgi tendon organ reflexes

02:02:23.660 | that are built into all of us

02:02:24.980 | that we arrive in this world with.

02:02:26.760 | And of course, the other forms of stretching

02:02:28.400 | that are known to be effective and important

02:02:30.960 | such as dynamic and ballistic stretching.

02:02:34.180 | Again, stretching protocols that involve a lot of momentum

02:02:37.920 | in order to improve range of motion for performance

02:02:41.460 | of particular types of work that one is about to embark on.

02:02:44.740 | Typically that would be physical work,

02:02:46.600 | but a whole interesting and unexplored landscape

02:02:50.540 | is the extent to which changing limb range of motion

02:02:53.780 | and different types of body movement

02:02:55.200 | actually shape our cognitive abilities.

02:02:57.620 | And that will be the topic of a future episode

02:02:59.940 | of this podcast.

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02:05:50.780 | So thank you once again for joining me today

02:05:52.840 | for a discussion about the neural and neuromuscular

02:05:56.420 | and connective tissue and skeletal aspects of flexibility

02:06:00.380 | and stretching.

02:06:01.580 | And as always, thank you for your interest in science.

02:06:04.460 | [upbeat music]

02:06:07.040 | (upbeat music)

Improve Flexibility with Research-Supported Stretching Protocols | Huberman Lab Podcast #76

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