WEBVTT 1 00:00:00.200 --> 00:00:04.200 Welcome to Huberman Lab Essentials, where we revisit past episodes 2 00:00:04.400 --> 00:00:07.639 for the most potent and actionable science based tools for 3 00:00:07.799 --> 00:00:12.839 mental health, physical health, and performance. I'm Andrew Huberman, and 4 00:00:12.880 --> 00:00:16.480 I'm a professor of neurobiology and ophthalmology at Stanford School 5 00:00:16.480 --> 00:00:19.399 of Medicine. Today we are going to discuss the science 6 00:00:19.440 --> 00:00:22.719 and practice of flexibility and stretching. The important thing that 7 00:00:22.719 --> 00:00:25.320 I'd like you to know is that flexibility and the 8 00:00:25.320 --> 00:00:30.079 process of stretching and getting more flexible involves three major components. 9 00:00:30.719 --> 00:00:35.880 Neural meaning of the nervous system, muscular muscles, and connective tissue. 10 00:00:36.039 --> 00:00:40.280 Connective tissue is the stuff that surrounds the neural stuff 11 00:00:40.320 --> 00:00:42.479 and the muscular stuff, although it's all kind of weaved 12 00:00:42.520 --> 00:00:45.520 together and braded together in complicated ways. So here's a 13 00:00:45.600 --> 00:00:47.600 key thing that everyone should know, whether or not you're 14 00:00:47.600 --> 00:00:53.280 talking about flexibility or not. Your nervous system controls your muscles. 15 00:00:53.679 --> 00:00:57.000 It's what gets your muscles to contract. So within your 16 00:00:57.039 --> 00:00:59.960 spinal cord, you have a category of neurons nerve cells 17 00:01:00.359 --> 00:01:04.159 that are called motor neurons. Those neurons release a chemical. 18 00:01:04.319 --> 00:01:08.120 That chemical is called acetyl coline. The release of acetylcholine 19 00:01:08.120 --> 00:01:11.719 from these nerve cells these neurons onto the muscles causes 20 00:01:11.760 --> 00:01:15.000 the muscles to contract. And when muscles contract, they are 21 00:01:15.040 --> 00:01:20.680 able to move limbs by way of changing the length 22 00:01:21.159 --> 00:01:25.560 of the muscle, adjusting the function of connective tissue like 23 00:01:25.599 --> 00:01:30.760 tendons and ligaments. Now, within the muscles themselves, there are 24 00:01:31.439 --> 00:01:35.159 nerve connections, and these are nerve connections that arise from 25 00:01:35.159 --> 00:01:37.200 a different set of neurons in the spinal cord that 26 00:01:37.239 --> 00:01:43.760 we call sensory neurons. These spindle connections within the muscle 27 00:01:43.840 --> 00:01:47.599 that wrap around the muscle fibers sense the stretch of 28 00:01:47.640 --> 00:01:51.319 those muscle fibers. So now we have two parts to 29 00:01:51.359 --> 00:01:54.359 the system that I've described. You've got motor neurons that 30 00:01:54.400 --> 00:01:58.480 can cause muscles to contract and shorten, and we have 31 00:01:58.920 --> 00:02:03.079 these spindles within the muscles themselves that wrap around the 32 00:02:03.159 --> 00:02:06.719 muscle fibers and that information is sent from the muscle 33 00:02:07.239 --> 00:02:10.599 back to the spinal cord. It's a form of sensing 34 00:02:10.680 --> 00:02:13.080 what's going on in the muscle. Now, why would that 35 00:02:13.080 --> 00:02:15.840 be useful? Well, what this does is it creates a 36 00:02:15.840 --> 00:02:19.639 situation where if a muscle or is stretching too much 37 00:02:19.759 --> 00:02:22.479 because the range of motion of a limb is increased 38 00:02:22.520 --> 00:02:25.680 too much, then the muscle will contract to bring that 39 00:02:26.080 --> 00:02:30.240 limb range of motion into a safe range. Again. Okay, 40 00:02:30.280 --> 00:02:32.759 so just to clarify, this whole thing looks like a 41 00:02:32.800 --> 00:02:35.879 loop and the essential components of the loop are motor 42 00:02:35.919 --> 00:02:40.319 neurons contract muscles. Sensory neurons that we call spindles are 43 00:02:40.319 --> 00:02:43.599 sensing stretched within the muscles, and if a given muscle 44 00:02:43.960 --> 00:02:48.599 is elongating because of the increased range of motion of 45 00:02:48.599 --> 00:02:51.960 a limb, those sensory neurons send an electrical signal into 46 00:02:51.960 --> 00:02:55.240 the spinal cord such that there is an activation of 47 00:02:55.280 --> 00:02:58.080 the motor neuron, which by now should make perfect sense 48 00:02:58.240 --> 00:03:01.199 as to why that's useful. It then short up the muscle. 49 00:03:01.240 --> 00:03:03.159 It actually doesn't really shorten the muscle, but it contracts 50 00:03:03.159 --> 00:03:06.439 the muscle that brings the limb back into a safe 51 00:03:06.520 --> 00:03:09.759 range of motion. So that's one basic mechanism that we 52 00:03:09.800 --> 00:03:12.159 want to hold in mind, this idea of a spindle 53 00:03:12.199 --> 00:03:15.159 that senses stretch and can activate contraction of the muscles 54 00:03:15.199 --> 00:03:18.120 and shorten the muscles. The next mechanism I want to describe, 55 00:03:18.240 --> 00:03:20.240 and once again there are only two that you need 56 00:03:20.280 --> 00:03:22.599 to hold in mind. For this episode has to do 57 00:03:22.759 --> 00:03:27.039 with sensing loads. So at the end of each muscles, 58 00:03:27.080 --> 00:03:33.439 you have tendons typically, and there are neurons that are 59 00:03:33.639 --> 00:03:38.719 closely associated with those tendons that are called Golgi tendon organs. Right. 60 00:03:38.800 --> 00:03:42.199 These are neurons that are sensory neurons that sense how 61 00:03:42.280 --> 00:03:44.800 much load is on a given muscle. Right, So, if 62 00:03:44.800 --> 00:03:47.879 you're lifting up something very very heavy, these neurons are 63 00:03:47.919 --> 00:03:50.479 going to fire, meaning they're going to send electrical activity 64 00:03:50.479 --> 00:03:53.639 into the spinal cord. And then those neurons have the 65 00:03:53.680 --> 00:03:58.680 ability to shut down, not activate, but shut down motor 66 00:03:58.719 --> 00:04:02.560 neurons and to prevent then the contraction of a given muscle. So, 67 00:04:02.639 --> 00:04:04.560 for instance, if you were to walk over and try 68 00:04:04.599 --> 00:04:08.159 and pick up a weight that is much too heavy 69 00:04:08.199 --> 00:04:10.919 for you, meaning you could not do it without injuring yourself. 70 00:04:11.039 --> 00:04:12.520 There are a number of reasons why you might not 71 00:04:12.560 --> 00:04:14.039 be able to lift it. But let's say you start 72 00:04:14.080 --> 00:04:15.680 to get it a little bit off the ground, or 73 00:04:15.680 --> 00:04:19.560 you start to get some force generator that would allow 74 00:04:19.600 --> 00:04:23.360 it to move, but the force that you're generating could 75 00:04:23.360 --> 00:04:27.000 potentially rip your muscles or your tendons off of the bone, 76 00:04:27.279 --> 00:04:30.720 right that it could disrupt the joints that could tear ligaments. Well, 77 00:04:30.759 --> 00:04:32.959 you have a safety mechanism in place. It's these Golgi 78 00:04:33.079 --> 00:04:36.720 tendon organs, these GTOs as they're called, that get activated 79 00:04:36.800 --> 00:04:39.439 and shut down the motor neurons and make it impossible 80 00:04:39.839 --> 00:04:43.439 for those muscles to contract. There are also mechanisms that 81 00:04:43.600 --> 00:04:47.800 arrive to the neuromuscular system from higher up in the 82 00:04:47.800 --> 00:04:51.720 nervous system, from the brain, and those mechanisms involve a 83 00:04:51.800 --> 00:04:55.120 couple of different facets that are really interesting and I 84 00:04:55.160 --> 00:04:57.240 think that we should all know about. In fact, today 85 00:04:57.240 --> 00:04:59.120 I'm going to teach you about a set of neurons 86 00:04:59.160 --> 00:05:01.800 that I'm guessing ninety nine point nine percent of you 87 00:05:01.839 --> 00:05:04.720 have never heard of, including all you neuroscientists out there, 88 00:05:04.759 --> 00:05:07.600 if you're out there, and I know you're out there, 89 00:05:08.399 --> 00:05:14.399 that seem uniquely enriched in humans and probably perform essential 90 00:05:14.480 --> 00:05:17.560 roles in our ability to regulate our physiology and our 91 00:05:17.560 --> 00:05:21.519 emotional state. So, within the brain, we have the ability 92 00:05:21.560 --> 00:05:24.920 to send things in the external world something we called xteroception, 93 00:05:25.120 --> 00:05:27.199 and we have the ability to send things in our 94 00:05:27.319 --> 00:05:31.399 internal world within our body called interoception. Interception can be 95 00:05:31.560 --> 00:05:33.680 the volume of food in your gut whether not you're 96 00:05:33.720 --> 00:05:36.319 experiencing any organ pain or discomfort, whether or not you 97 00:05:36.399 --> 00:05:38.560 feel good in your gut and in your organs. The 98 00:05:38.639 --> 00:05:42.360 main brain area that's associated with interpreting what's going on 99 00:05:42.399 --> 00:05:45.720 in our body is called the insula I nsula. It's 100 00:05:45.759 --> 00:05:48.519 a very interesting brain region. It's got two major parts. 101 00:05:48.560 --> 00:05:52.800 The front of it is mainly concerned with things like 102 00:05:53.360 --> 00:05:56.959 smell and to some extent vision, like if you smell 103 00:05:56.959 --> 00:05:58.800 something good to approach it, or if you smell something 104 00:05:58.839 --> 00:06:02.480 bad to avoid it. Posterior insula the back of the insula, 105 00:06:02.519 --> 00:06:06.920 that is, has a very interesting and distinct set of functions. 106 00:06:07.759 --> 00:06:11.360 The posterior insula is mainly concerned with what's going on 107 00:06:11.560 --> 00:06:15.839 with your somatic experience, how do you feel internally? Mainly 108 00:06:15.879 --> 00:06:18.639 batches information into yum, I want to keep doing this 109 00:06:18.759 --> 00:06:22.839 or approach this thing, or continue down some path of 110 00:06:23.519 --> 00:06:27.439 movement or eating or staying in a temperature environment, et cetera. 111 00:06:27.959 --> 00:06:29.600 Or yuck. I need to get out of here. I 112 00:06:29.600 --> 00:06:31.079 don't want any more of this. I don't want to 113 00:06:31.120 --> 00:06:34.199 keep doing this. This is painful or reversive or stressful. 114 00:06:34.480 --> 00:06:39.800 In your posterior insula, you have a very interesting population 115 00:06:39.879 --> 00:06:44.199 of very large neurons. These are exceptionally large neurons called 116 00:06:44.639 --> 00:06:49.519 then economone neurons, neurons that are again unbeknownst to most neuroscientists, 117 00:06:49.560 --> 00:06:54.959 and they seem uniquely enriched in humans. Why is that interesting, Well, 118 00:06:55.120 --> 00:06:59.920 these then Economoe neurons have the unique property of interg 119 00:07:00.040 --> 00:07:05.399 grading our knowledge about our body movements, our sense of 120 00:07:05.480 --> 00:07:10.079 pain and discomfort, and can drive motivational processes that allow 121 00:07:10.160 --> 00:07:13.680 us to lean into discomfort and indeed to overcome any 122 00:07:13.720 --> 00:07:16.160 discomfort if we decide that the discomfort that we are 123 00:07:16.199 --> 00:07:20.560 experiencing is good for us or directed toward a specific goal. 124 00:07:20.800 --> 00:07:24.639 And then there's the other really interesting aspect of these 125 00:07:24.720 --> 00:07:28.439 van Economo neurons, which is that these van Economo neurons 126 00:07:28.639 --> 00:07:31.879 are connected to a number of different brain areas that 127 00:07:32.000 --> 00:07:34.639 can shift our internal state from one of so called 128 00:07:34.680 --> 00:07:39.040 sympathetic activation. So this is a pattern of alertness and 129 00:07:39.120 --> 00:07:43.199 even stress, sometimes even panic, but typically alertness and stress 130 00:07:43.439 --> 00:07:48.839 to one so called parasympathetic activation, to one of relaxation. 131 00:07:49.360 --> 00:07:52.720 Oftentimes you'll hear that stretching should be done by relaxing 132 00:07:52.759 --> 00:07:55.079 into the stretch. Well, what does it actually mean to 133 00:07:55.120 --> 00:07:59.160 relax into the stretch? Well, these van Economo neurons sit 134 00:07:59.279 --> 00:08:01.920 at this juncture where they're able to evaluate what's going 135 00:08:01.959 --> 00:08:05.519 on inside our body and allow us to access neural 136 00:08:05.560 --> 00:08:09.199 circuitries by which we can shift our relative level of 137 00:08:09.319 --> 00:08:13.120 alertness down a bit, or our relative level of stress 138 00:08:13.439 --> 00:08:17.839 down a bit, and thereby to increase so called parasympathetic 139 00:08:17.920 --> 00:08:23.000 activation and to literally override some of those spindle mechanisms, 140 00:08:23.480 --> 00:08:27.720 even the gto mechanisms, but especially the spindle mechanisms at 141 00:08:27.759 --> 00:08:31.839 the neuromuscular and muscular spinal junction. I'll give you a 142 00:08:31.879 --> 00:08:34.200 brief example of this that you've already done in your 143 00:08:34.240 --> 00:08:36.799 life and that we all have the capacity for. What 144 00:08:36.840 --> 00:08:41.080 I'm referring to is the monosynaptic stretch reflex. This is 145 00:08:41.080 --> 00:08:44.519 something that every first year neuroscience graduate student learns, which 146 00:08:44.559 --> 00:08:46.840 is that if you were to step on a sharp 147 00:08:46.879 --> 00:08:49.519 object with a bare foot, you would not need to 148 00:08:49.519 --> 00:08:53.200 make the decision to retract your foot. You would automatically 149 00:08:53.240 --> 00:08:56.120 do that provided you have a healthy nervous system. There 150 00:08:56.120 --> 00:08:59.399 are mechanisms in place that cause the retraction of that 151 00:08:59.480 --> 00:09:03.799 limb by way of ensuring that the proper muscles contract 152 00:09:04.000 --> 00:09:06.600 and other muscles do not contract, in fact, that they 153 00:09:06.639 --> 00:09:09.519 fully relax. Okay, so in the case of stepping on 154 00:09:09.559 --> 00:09:11.480 a sharp object like a piece of glass or a 155 00:09:11.559 --> 00:09:15.120 nail or attack, you would essentially activate the hip flexer 156 00:09:15.200 --> 00:09:18.639 to lift up your foot as quickly as possible. In 157 00:09:18.759 --> 00:09:24.159 doing so, that same neural circuit would activate a contraladal, 158 00:09:24.240 --> 00:09:27.720 meaning opposite side of the body circuit to ensure that 159 00:09:27.799 --> 00:09:30.879 the leg the foot that's not stepping on the sharp object, 160 00:09:31.080 --> 00:09:34.200 would do exactly the opposite and would extend to make 161 00:09:34.200 --> 00:09:37.799 sure that you don't fall over. All of that happens reflexively. 162 00:09:37.879 --> 00:09:41.840 It does not require any thought or decision making. However, 163 00:09:43.000 --> 00:09:47.240 if your life depended on walking across some sharp objects, 164 00:09:47.360 --> 00:09:49.639 let's say, let's make it a little less dramatic, so 165 00:09:49.679 --> 00:09:51.519 it's not like the Diehard movie or something where you 166 00:09:51.559 --> 00:09:54.879 have to run barefoot across the glass, although that's a 167 00:09:54.919 --> 00:09:57.600 pretty good example of what I'm describing here. But let's 168 00:09:57.600 --> 00:09:59.960 say you had to walk across some very hot stone 169 00:10:00.639 --> 00:10:03.519 to get away from something that you wanted to avoid. 170 00:10:04.159 --> 00:10:07.799 You could override that stretch reflex by way of a 171 00:10:07.840 --> 00:10:10.360 decision made with your upper motor neurons, your insula, and 172 00:10:10.399 --> 00:10:13.440 your cognition, and almost certainly those van Economoe neurons, which 173 00:10:13.440 --> 00:10:15.320 would be screaming don't do this, don't do this, don't 174 00:10:15.320 --> 00:10:18.120 do this, could shuttle that information to brain areas that 175 00:10:18.159 --> 00:10:21.720 would allow you to override the reflex and essentially push 176 00:10:21.759 --> 00:10:26.039 through the pain and maybe even in fact, even not 177 00:10:26.159 --> 00:10:29.559 experience the pain to the same degree or even at all. 178 00:10:29.679 --> 00:10:33.320 So these van economoeurons sit at a very important junction 179 00:10:33.440 --> 00:10:35.919 within the brain. They pay attention to what's going on 180 00:10:36.000 --> 00:10:40.039 in your body pain, pleasure, et cetera, and that includes 181 00:10:40.039 --> 00:10:41.960 what's going on with your limbs and your limb range 182 00:10:42.000 --> 00:10:46.120 of motion. They also are paying attention and can control 183 00:10:46.240 --> 00:10:50.399 the amount of activation, kind of alertness or calmness that 184 00:10:50.440 --> 00:10:54.759 you are able to create within your body in response 185 00:10:54.799 --> 00:10:59.039 to a given sensory experience. And as I mentioned before, 186 00:10:59.080 --> 00:11:01.720 they seem to be uniquely enriched in humans. They seem 187 00:11:01.759 --> 00:11:05.320 to be related to the aspects of our evolution that 188 00:11:05.440 --> 00:11:08.480 allow us to make decisions about what to do with 189 00:11:08.600 --> 00:11:11.559 our body in ways that other animals just simply can't. 190 00:11:11.879 --> 00:11:13.759 I'd like to take a quick break and acknowledge one 191 00:11:13.799 --> 00:11:17.000 of our sponsors, Element Element is an electrolyte drink that 192 00:11:17.039 --> 00:11:19.759 has everything you need and nothing you don't. That means 193 00:11:19.799 --> 00:11:23.279 the electrolytes sodium, magnesium, and potassium in the correct amounts, 194 00:11:23.360 --> 00:11:26.559 but no sugar. Proper hydration is critical for optimal brain 195 00:11:26.679 --> 00:11:29.799 and body function. Even a slight degree of dehydration can 196 00:11:29.840 --> 00:11:33.399 diminish cognitive and physical performance. 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Broadly defined, we can describe these as dynamic, ballistic, static, 223 00:12:54.720 --> 00:13:00.720 and what's called PNF stretching. PNF stands for appropriateceptive neuromuscular facilitation. 224 00:13:01.200 --> 00:13:04.639 The first two dimension. Dynamic and ballistic stretching both involves 225 00:13:04.679 --> 00:13:08.519 some degree of momentum and can be distinguished from static 226 00:13:08.600 --> 00:13:12.960 and PNF type stretching. Now to distinguish dynamic stretching from 227 00:13:12.960 --> 00:13:16.679 ballistic stretching, like to focus on this element of momentum. 228 00:13:17.279 --> 00:13:21.799 Both involve moving a limb through a given range of motion. 229 00:13:23.279 --> 00:13:26.840 In dynamic stretching, however, it tends to be more controlled, 230 00:13:27.039 --> 00:13:30.039 less use of momentum, especially towards the N range of motion, 231 00:13:30.320 --> 00:13:33.399 whereas in ballistic stretching there tends to be a bit 232 00:13:33.440 --> 00:13:37.559 more swinging of the limb or use of momentums. But again, 233 00:13:37.840 --> 00:13:41.799 dynamic and ballistic stretching both involve movement, so we have 234 00:13:41.840 --> 00:13:44.399 to generate some force in order to create that movement. 235 00:13:45.279 --> 00:13:48.399 Ballistic stretching involving a bit more momentum or sometimes a 236 00:13:48.399 --> 00:13:51.799 lot more momentum, especially at the N range of motion. Now, 237 00:13:51.840 --> 00:13:55.200 both of those are highly distinct from static stretching, which 238 00:13:55.200 --> 00:13:58.720 involves holding the N range of motion, so minimizing the 239 00:13:58.720 --> 00:14:01.679 amount of momentum that's here used. Static stretching can be 240 00:14:01.720 --> 00:14:05.720 further subdivided into active or passive. Right, there are different 241 00:14:06.279 --> 00:14:09.200 names for these kinds of approaches. You can hear about 242 00:14:09.200 --> 00:14:11.600 the Andersen approach or the gender approach. You can look 243 00:14:11.639 --> 00:14:15.399 these sorts of things up online. There's also passive static stretching, 244 00:14:15.639 --> 00:14:19.039 in which it's more of a relaxation into a further 245 00:14:19.120 --> 00:14:21.159 range of motion, and that can be a subtle distinction, 246 00:14:21.200 --> 00:14:25.279 and nonetheless, static stretching involves both those types of elements 247 00:14:25.320 --> 00:14:29.559 active and passive, but is really about eliminating momentum. And 248 00:14:29.639 --> 00:14:33.799 then there's the PNF. The propriate receptive neuromuscular facilitation and 249 00:14:34.039 --> 00:14:37.600 propriate reception has several different meanings in the context of 250 00:14:37.720 --> 00:14:41.159 neuroscience and physiology. To just keep it really simple for today, 251 00:14:41.360 --> 00:14:45.279 propriate reception involves both a knowledge and understanding of where 252 00:14:45.320 --> 00:14:48.759 our limbs are in space and relative to our body, 253 00:14:49.000 --> 00:14:51.559 typically relative to the midline. So the brain is often 254 00:14:51.759 --> 00:14:54.559 trying to figure out where are our limbs relative to 255 00:14:54.600 --> 00:14:56.919 our midline down the center of our body. And if 256 00:14:56.960 --> 00:15:01.279 your goal is to increase your hamstring flexibility, the flexibility 257 00:15:01.360 --> 00:15:04.799 and range of motion of other related muscle systems, you 258 00:15:04.879 --> 00:15:08.840 might put a strap around your ankle and pull that 259 00:15:08.960 --> 00:15:11.879 muscle where I should say, excuse me, that limb towards. 260 00:15:11.919 --> 00:15:13.519 You're not gonna pull the muscle towards. You can pull 261 00:15:13.559 --> 00:15:15.679 that limb, your ankle towards you try and get it 262 00:15:15.679 --> 00:15:19.200 sort of back over your head and then progressively relaxing 263 00:15:19.240 --> 00:15:22.759 into that or maybe even putting some additional force to 264 00:15:22.919 --> 00:15:25.480 push the end range of motion and then relaxing it 265 00:15:25.759 --> 00:15:28.799 and then actually trying to stretch that same limb or 266 00:15:28.840 --> 00:15:32.320 increase the limb range of motion without the strap. There's 267 00:15:32.399 --> 00:15:35.840 a huge range of PNF protocols. Those protocols can be 268 00:15:35.960 --> 00:15:40.000 done both by oneself with or without straps, with machines 269 00:15:40.039 --> 00:15:45.120 with actual weights, or with training partners, so specific exercises 270 00:15:45.159 --> 00:15:48.080 to target specific muscle groups aside, we've now established that 271 00:15:48.159 --> 00:15:51.279 there are four major categories of stretching, or at least 272 00:15:51.279 --> 00:15:54.039 those are the four major categories I'm defining today. But 273 00:15:54.080 --> 00:15:57.120 in terms of increasing limb range of motion in the 274 00:15:57.240 --> 00:16:01.600 long term, of truly becoming more flexible as opposed to 275 00:16:01.639 --> 00:16:06.320 transiently more flexible, static stretching, which includes PNF, appears to 276 00:16:06.360 --> 00:16:07.960 be the best route to go. So, whether or not 277 00:16:08.039 --> 00:16:12.639 you want to maintain, re establish, or gain limb range 278 00:16:12.679 --> 00:16:17.080 of motion, static stretching of holds of thirty seconds appear 279 00:16:17.159 --> 00:16:20.039 to be best. Now, the question is how long should 280 00:16:20.080 --> 00:16:21.759 you do that? And how many sets should you do that? 281 00:16:21.799 --> 00:16:23.399 And how many times a week should you do that? 282 00:16:23.600 --> 00:16:26.039 To answer those questions, when to turn to what I 283 00:16:26.039 --> 00:16:28.600 think is a really spectacular review. The title of the 284 00:16:28.600 --> 00:16:32.240 paper is the relation between stretching typology and stretching duration 285 00:16:32.679 --> 00:16:35.399 the effects on range of motion. First of all, and 286 00:16:35.480 --> 00:16:39.519 I quote, all stretching typologies showed range of motion improvements 287 00:16:39.559 --> 00:16:42.360 over a long term period. However, the static protocols showed 288 00:16:42.480 --> 00:16:45.240 significant gains with a P value lesson point zero five, 289 00:16:45.320 --> 00:16:49.399 which means a probability that cannot be explained by chance 290 00:16:49.480 --> 00:16:53.279 alone when compared to ballistic or PNF protocols. So again, 291 00:16:53.320 --> 00:16:55.799 what we're hearing is that static stretching is the preferred 292 00:16:55.840 --> 00:16:59.080 mode for increasing limb range of motion, although here they 293 00:16:59.120 --> 00:17:03.679 make the additional point that static stretching might even be superior, 294 00:17:03.720 --> 00:17:08.079 not just to ballistic stretching, but also to PNF protocols. 295 00:17:08.240 --> 00:17:11.279 The authors go on to say time spent stretching per 296 00:17:11.279 --> 00:17:14.599 week seems fundamental to illicit range of movement improvements when 297 00:17:14.599 --> 00:17:17.640 stretches are applied for at least or more than five 298 00:17:17.720 --> 00:17:21.039 minutes per week. Okay, this is critical. This is not 299 00:17:21.160 --> 00:17:24.880 five minutes per stretch, remember thirty seconds per static stretch, 300 00:17:24.920 --> 00:17:27.200 but at least five minutes per week. So what this 301 00:17:27.359 --> 00:17:30.799 means is that we should probably be doing anywhere from 302 00:17:30.880 --> 00:17:35.720 two to four sets of thirty second static hold stretches 303 00:17:36.119 --> 00:17:39.279 five days per week. So what would effective stretching protocol. 304 00:17:39.279 --> 00:17:42.799 Look like we're all trying to improve limb range of 305 00:17:42.839 --> 00:17:45.839 motion for different limbs and different muscle groups. Let's talk 306 00:17:45.839 --> 00:17:49.559 about hamstrings for the time being. This could of course 307 00:17:49.599 --> 00:17:51.880 be applied to other muscle groups. Let's say you want 308 00:17:51.880 --> 00:17:56.079 to improve hamstring flexibility and limb range of motion about 309 00:17:56.079 --> 00:18:00.279 and around the hamstring and involving the hamstring. I want 310 00:18:00.279 --> 00:18:04.519 to do three sets of static stretching for the hamstring. 311 00:18:04.920 --> 00:18:09.200 You would do that by holding the stretch for thirty seconds, 312 00:18:09.519 --> 00:18:12.039 resting some period of time, and doing it again, holding 313 00:18:12.079 --> 00:18:14.759 for thirty seconds, resting some period of time, and then 314 00:18:15.519 --> 00:18:18.079 holding it for thirty seconds. That would be one training 315 00:18:18.079 --> 00:18:20.240 session for the hamstrings. I have to imagine that you'd 316 00:18:20.240 --> 00:18:22.680 probably want to stretch other muscle groups as well in 317 00:18:22.720 --> 00:18:27.279 that same session. So three sets of thirty seconds each 318 00:18:28.039 --> 00:18:31.559 get ninety seconds, and you would do that ideally five 319 00:18:31.599 --> 00:18:34.640 times a week or maybe even more. One thing that 320 00:18:34.839 --> 00:18:38.039 did show up in my exploration of the peer reviewed 321 00:18:38.079 --> 00:18:40.799 research is this notion of warming up for all this. 322 00:18:40.880 --> 00:18:43.519 We haven't talked about that yet. In general, to avoid injury, 323 00:18:43.559 --> 00:18:45.599 it's a good idea to raise your core body temperature 324 00:18:45.599 --> 00:18:49.039 a bit before doing these kinds of stretches, even these 325 00:18:49.079 --> 00:18:51.400 static stretches, which we can sort of ease into and 326 00:18:51.519 --> 00:18:57.480 don't involve ballistic movement by definition, and the basic takeaway 327 00:18:57.599 --> 00:19:00.359 that I was able to find was that if we 328 00:19:00.400 --> 00:19:03.839 are already warm from running or from weight training, or 329 00:19:03.880 --> 00:19:08.559 from some other activity, that doing the static stretching practice 330 00:19:08.599 --> 00:19:11.839 at the end of that weight training or cardiovascular or 331 00:19:11.880 --> 00:19:15.079 other physical session would allow us to go immediately into 332 00:19:15.119 --> 00:19:19.880 the stretching session because we're already warm, so to speak. Otherwise, 333 00:19:20.599 --> 00:19:23.480 raising one's core body temperature by a bit by doing 334 00:19:24.119 --> 00:19:28.200 five to seven, maybe even ten minutes of easy cardiovascular 335 00:19:28.200 --> 00:19:31.119 exercise or calistenic movements, provided you can do those without 336 00:19:31.119 --> 00:19:34.119 getting injured, seems to be an ideal way to warm 337 00:19:34.200 --> 00:19:36.839 up the body for stretching. We should be warm or 338 00:19:36.880 --> 00:19:39.160 warm up to stretch, although those warm ups don't have 339 00:19:39.200 --> 00:19:42.160 to be extremely extensive, And then just by way of logic, 340 00:19:42.279 --> 00:19:46.240 doing the static stretching after resistance training or cardiovascular training 341 00:19:46.400 --> 00:19:49.359 seems to be most beneficial in fact, and unfortunately we 342 00:19:49.400 --> 00:19:50.799 don't have time to go into this in too much 343 00:19:50.839 --> 00:19:52.960 detail today. I was able to find a number of 344 00:19:53.000 --> 00:19:58.079 papers that make the argument that static stretching prior to 345 00:19:58.119 --> 00:20:03.480 cardiovascular training and maybe even prior to resistance training, can 346 00:20:03.839 --> 00:20:07.960 limit our performance in running and resistance training. I realize 347 00:20:08.000 --> 00:20:11.200 that's a controversial area. You have those who say no, 348 00:20:11.319 --> 00:20:14.279 it's immensely beneficial. You have those who say no, it 349 00:20:14.319 --> 00:20:17.559 inhibits performance, and those that say no, it's a matter 350 00:20:17.599 --> 00:20:19.960 of how exactly you perform that static stretching and which 351 00:20:20.079 --> 00:20:22.039 muscle groups and how you're doing this, and how much 352 00:20:22.039 --> 00:20:25.039 time in between static stretching and performance. But to leave 353 00:20:25.079 --> 00:20:28.240 all that aside, doing static stretching after some other form 354 00:20:28.240 --> 00:20:32.799 of exercise, and if not, after some form of exercise, 355 00:20:32.880 --> 00:20:34.680 after a brief warm up to raise your core body 356 00:20:34.680 --> 00:20:37.799 temperature definitely seems like the right way to go. I'd 357 00:20:37.839 --> 00:20:40.079 like to take a quick break and acknowledge our sponsor 358 00:20:40.240 --> 00:20:44.119 eight Sleep eight Sleep make smart mattress covers with cooling, heating, 359 00:20:44.160 --> 00:20:46.680 and sleep tracking capacity. 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If you'd like to 379 00:21:39.519 --> 00:21:42.240 try eight sleep, go to eight sleep dot com slash 380 00:21:42.279 --> 00:21:44.599 huberman to get up to three hundred and fifty dollars 381 00:21:44.680 --> 00:21:46.920 off the new Pod five. Eight sleep ships to many 382 00:21:46.960 --> 00:21:51.000 countries worldwide, including Mexico and the UAE. Again, that's eight 383 00:21:51.000 --> 00:21:53.799 sleep dot com slash huberman to save up to three 384 00:21:53.880 --> 00:21:56.720 hundred and fifty dollars. I'm guessing that most people are 385 00:21:56.759 --> 00:22:00.359 not doing five days a week of dedicated statics stretch 386 00:22:00.519 --> 00:22:05.240 range of motion directed training, but it does appear that 387 00:22:05.240 --> 00:22:08.480 that frequency about the week getting those repeated sessions, even 388 00:22:08.480 --> 00:22:10.880 if they are short for an individual muscle group, turns 389 00:22:10.920 --> 00:22:13.000 out to be important. They're going to offset the age 390 00:22:13.000 --> 00:22:16.960 related losses in flexibility for sure, if one is dedicated 391 00:22:17.000 --> 00:22:19.279 about these practices. Some of you may be familiar with 392 00:22:19.319 --> 00:22:21.599 this so called Anderson method. It's been around for a 393 00:22:21.599 --> 00:22:24.640 long time. Anderson has an interesting idea in principle which 394 00:22:24.640 --> 00:22:27.599 has thread through a lot of his teachings that I 395 00:22:27.640 --> 00:22:29.759 think are very much in keeping with the study that 396 00:22:29.799 --> 00:22:35.079 I'm about to describe next, where he emphasizes, yes, to 397 00:22:35.480 --> 00:22:38.400 stretch to the end of the range of motion, but 398 00:22:38.559 --> 00:22:40.799 not to focus so much on where that range of 399 00:22:40.839 --> 00:22:45.799 motion happens to be that day. So for instance, not thinking, oh, 400 00:22:45.839 --> 00:22:49.119 I can always touch my toes, for instance, and therefore 401 00:22:49.200 --> 00:22:53.160