Dr. Andy Galpin: How to Build Strength, Muscle Size & Endurance

Andrew Huberman 0:00 (peaceful music) Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, my guest is Dr. Andy Galpin. Dr. Galpin is a full and tenured professor in the Department of Kinesiology at California State University in Fullerton. He is also a world expert in all things exercise science and kinesiology. Today, you are going to hear what is essentially a master class in how to build fitness, no matter what level of fitness you happen to have. He talks about how to build endurance and the multiple types of endurance. He talks about how to build strength and hypertrophy, which is the growth of muscle fibers. So if you're seeking to get stronger or build bigger muscles or build endurance, or all of those things, today you're going to learn how. You're also going to learn how to build flexibility, how to hydrate properly for exercise, and we'll also talk about nutrition and supplementation. What makes Dr. Galpin so unique is his ability to span all levels of exercise science. He has the ability to clearly communicate the sets and repetition schemes that one would want to follow, for instance, to build more strength or to build larger muscles. He also clearly describes exactly how to train if you want to build more endurance or enhance cardiovascular function. What's highly unique about Dr. Galpin and the information he teaches and the way he communicates that information is that he can take specific recommendations of how recreational exercisers or even professional athletes ought to train for their specific goals and link that to specific mechanisms, that is, the specific changes that need to occur in the nervous system and in muscle fibers, and indeed right down to the genetics of individual cells in your brain and body in order for those exercise adaptations to occur. It's truly rare to find somebody that can span so many different levels of analyses and who is able to communicate all those levels of understanding in such a clear and actionable way. Indeed, Dr. Galpin is one of just a handful of people to which I and many others look when they want to make sure that the information that they're getting about exercise is gleaned from quality peer-reviewed studies, hands-on experience with a wide variety of research subjects, meaning everyday people all the way up to professional athletes in a wide variety of sports. So it's no surprise that he's not only one of the most knowledgeable, but also the most trusted voices in exercise science. Dr. Galpin is also an avid communicator of zero-cost-to-consumer information about exercise science. You can find him on Instagram @drandygalpin and also on Twitter @DrAndyGalpin. Both places he provides terrific information about recent studies, both from his laboratory and from other laboratories, more in-depth protocols of the sort that you'll hear about today. So if you're not already following him, be sure to do so. He provides only the best information. He's extremely nuanced and precise and clear in delivering that information. I'm certain that by the end of today's conversation you'll come away with a tremendous amount of new knowledge that you can devote to your exercise pursuits. I'm pleased to announce that

Andrew Huberman 3:08 I'm hosting two live events this May. The first live event will be hosted in Seattle, Washington on May 17th. The second live event will be hosted in Portland, Oregon on May 18th. Both are part of a lecture series entitled The Brain-Body Contract, during which I will discuss science and science-based tools for mental health, physical health, and performance. And I should point out that while some of the material I'll cover will overlap with information covered here on the Huberman Lab Podcast and on various social media posts, most of the information I will cover is going to be distinct from information covered on the podcast or elsewhere. So once again, it's Seattle on May 17th, Portland on May 18th. You can access tickets by going to hubermanlab.com/tour, and I hope to see you there. Before we begin, I'd like to emphasize that this podcast is

Andrew Huberman 3:55 separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero-cost-to-consumer information about science and science-related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is Athletic Greens. Athletic Greens is an all-in-one vitamin mineral probiotic drink. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking Athletic Greens and the reason I still take Athletic Greens once or twice a day is that it helps me cover all of my basic nutritional needs. It makes up for any deficiencies that I might have. In addition, it has probiotics, which are vital for microbiome health. I've done a couple of episodes now on the so-called gut microbiome and the ways in which the microbiome interacts with your immune system, with your brain to regulate mood, and essentially with every biological system relevant to health throughout your brain and body. With Athletic Greens, I get the vitamins I need, the minerals I need, and the probiotics to support my microbiome. If you'd like to try Athletic Greens, you can go to athleticgreens.com/huberman and claim a special offer. They'll give you five free travel packs, which make it easy to mix up Athletic Greens while you're on the road, plus a year's supply of vitamin D3 K2. There are a ton of data now showing that vitamin D3 is essential for various aspects of our brain and body health. Even if we're getting a lot of sunshine, many of us are still deficient in vitamin D3, and K2 is also important because it regulates things like cardiovascular function, calcium in the body, and so on. Again, go to athleticgreens.com/huberman to claim the special offer of the five free travel packs and the year's supply of vitamin D3 K2. Today's episode is also brought to us by Thesis. Thesis makes what are called nootropics, which means smart drugs. Now to be honest, I am not a fan of the term s- nootropics. I don't believe in smart drugs in the sense that I don't believe that there's any one substance or collection of substances that can make us smarter. I do believe based on science, however, that there are particular neural circuits and brain functions that allow us to be more focused, more alert.... access creativity, be more motivated, et cetera. That's just the way that the brain works, different neural circuits for different brain states. And so the idea of a nootropic that's just going to make us smarter all around fails to acknowledge that smarter is many things, right? 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My go-to formula is the clarity formula, or sometimes I'll use their energy formula be- before training. To get your own personalized nootropic starter kit, go online to takethesis.com/huberman, take a three-minute quiz, and Thesis will send you four different formulas to try in your first month. That's takethesis.com/huberman and use the code Huberman at checkout for 10% off your first order. Today's episode is also brought to us by InsideTracker. InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and help you reach your health goals. I've long been a believer in getting regular blood work done, for the simple reason that many of the factors that impact your immediate and long-term health can only be assessed with a quality blood test. What's unique about InsideTracker is that while there are a lot of different tests out there for hormones and metabolic factors, et cetera, with InsideTracker you get the numbers back in terms of your levels, but they also give you very clear directives in terms of lifestyle, nutrition, and supplementation, that can help you bring those values into the ranges that are best for you and your health goals. And that's very different than a lot of the other programs where you get a lot of information but you don't really know what to do with that information. InsideTracker makes that all very easy to understand and very actionable based on the very easy-to-use dashboard at InsideTracker. If you'd like to try InsideTracker, you can visit insidetracker.com/huberman to get 20% off any of InsideTracker's plans. Just use the code Huberman at checkout. And now for my discussion with Dr.

Andrew Huberman 8:20 Andy Galpin. Welcome Doctor, Professor Andy Galpin. It's been a long time coming. We have friends in common, but this is actually the first time we've sat down face to face.

Dr. Andy Galpin 8:30 Yeah. I'm very excited.

Andrew Huberman 8:31 Yeah. There are only a handful, meaning about three or four people, who I trust enough in the exercise physiology space that when they speak, I not only listen, but I modify my protocols, and you are among those three or four people. So first of all, a debt of gratitude. Thank you. Uh, you've greatly shaped the protocols that I use, and, um, I know there's far more for me and for others to learn. So you're a professor, you teach in university, and you have a tremendous range of levels of exploration. Muscle biopsy, literally images down the microscope, all the way to training professional athletes and everything in between. So you are truly an n-of-one. And just to start us off, I would love to have you share with us what you think most everybody or even everybody should know about principles of strength training, principles of endurance training, and principles of, let's call it hypertrophy, power, and the other ki- sort of categories of training. And this could be very top contour, but what do you think everybody on planet Earth should know about these categories of personal and athletic development?

Dr. Andy Galpin 9:45 Well, that's a great first question. (laughs) Holy cow. Uh, I think I'll start it this way. I tend to think about, um, there's about nine different adaptations you can get from exercise. Um, fat loss is not one of those. It is a byproduct, but that's not really what I'm getting at. Um, and so we can kind of categorize everything like that, and what we're going to, we can talk about are what are the concepts that you need to hit within each one, and then you could have infinite discussion of the different methodologies, right? And so that, that first thing to hit is the concepts are actually fairly few, but the methods are many, right? People have said that in iterations throughout time. Um, so if you walk from the very beginning, the first one to think about is what we'll just call skill. So this is improving anything from, say, a golf swing to a squatting technique to running. And this is just simply moving mechanically how you want your body to move. I'm just going to globally call that skill. From there, we're going to get into speed. So this is moving as fast as possible. The next one is power. And power is a function of speed, but also a function of the next one, which is strength. So if you actually multiply strength by speed, you get power. And the reason I'm making this distinction, by the way, is some of these are very close and I'm going in a specific order on purpose here. For example, power is, like I just said, it's a function of speed and strength. So if you improve speed, you've also likely improved power. But not necessarily, right? 'Cause it could have come from the force direction either. So there's carryover. So, like, a lot of things that you would do for the development of strength and power, um, they are somewhat similar, but then there's differences, right? So things that you would do correctly for power would really not develop much strength and vice versa. So, and we can get into all these details later. Once you get past strength, then the next one kind of down the list is hypertrophy. This is muscle size, right? Growing muscle mass is one way to think about it. After hypertrophy, you get into these categories of the next one is, um, these are all globally endurance-based issues, and the very first one is called muscular endurance. So this is your ability to do, how many push-ups can you do in one minute, you know, things like that. Past, um, muscular endurance, you're now into more of an energetic or even cardiovascular fatigue. So you've left the local muscle and you're now into the entire physiological system.... and its ability to produce and sustain work. And we can get into a bunch of differentiations with an endurance, but, uh, just to keep it really simple right now, the very first one, think about this as, um, I call this anaerobic power, right? So this is your ability to produce a lot of work for, say, 30 seconds to maybe one minute, kind of two minutes like that. The next one down then is more closely aligned to what we'll call your VO2 max. So this is your ability to kind of do the same thing, but more of a time domain of, say, three to 12 minutes. So this is going to be a maximal heart rate, but it's going to be well past just max heart rate. Then after that, we have what I call long duration endurance. So this is your ability to sustain work. The time domain doesn't matter in terms of how fast go- you're going. It's how c- how long can you sustain work? This is 30-plus minutes of no break, like that. So as just an high-level overview, those are the, the different things you can target. Um, and again, some of those cross over, and some are actually a little bit contrarian to the other ones. So pushing towards one is maybe gonna sacrifice something else. So as a, as an overall start, that's really what we're looking at. Within all those though, they do have similar concepts in terms of there is a handful of things you have got to do to make all of those things work, and we could talk about as many of those as you want, but one of them is functionally called progressive overload. So w- whichever one you're trying to improve at, if you want to continue to improve, you have to have some method of overload, and a- as you well know, you've talked about a lot, adaptation physiologically happens as a byproduct of stress. So you have to push the system. So if you continue to do, say, the exact same workout over time, you better not expect much improvement. You can keep maintenance, but you're not going to be adding additional stress. So in general, you have to have some sort of progressive overload, and we can talk in detail about what that means for each category. But this could come from adding more weights. This could come from adding more repetitions. It could come from doing it more often in the week. It could come from adding complexity to the movement, so going from, say, a partial range of motion to a full range of motion, or adding other variables. So there's a lot of different ways to progress. But you have to have some sort of movement forward. So if you have this kind of routine where you've built Monday, Wednesday, and Saturday or something, and you just do that infinitely, um, you're not going to get very far. So that's, I guess, the most high-level overview of all the things people can go after, and then we can go from whatever direction you want from there.

Andrew Huberman 14:29 Well, I'd love to do the deep dive on each one of these-

Dr. Andy Galpin 14:32 Yeah, man.

Andrew Huberman 14:32 ... for, uh, several hours, um, but, uh, and I imagine that over time we probably will. Uh,

Andrew Huberman 14:40 I'd love to chat about a couple of these in a bit more depth. So in terms of defining what the progressive overload variables are-

Dr. Andy Galpin 14:47 Yeah.

Andrew Huberman 14:47 ... for these different categories, maybe we could hit the, um, two most common combinations of these nine things, the first one being, um, strength and hypertrophy-

Dr. Andy Galpin 14:58 Yep.

Andrew Huberman 14:58 ... and maybe we could lump power in there. Um, maybe not. Uh, you're the, you're the exercise physio-

Dr. Andy Galpin 15:03 Yes and no.

Andrew Huberman 15:03 ... physiologist.

Dr. Andy Galpin 15:04 Yeah.

Andrew Huberman 15:04 But strength and hypertrophy, which at least bear some relationship.

Dr. Andy Galpin 15:07 Yeah.

Andrew Huberman 15:07 And then maybe separately, we could explore, um, sustained work endurance, this 30 minutes-

Dr. Andy Galpin 15:13 Yeah.

Andrew Huberman 15:13 ... or longer continuously, 'cause I think many people train in that regime.

Dr. Andy Galpin 15:16 Yeah.

Andrew Huberman 15:16 Um, and probably, uh, something like, uh, VO2 max a- anaerobic as-

Dr. Andy Galpin 15:23 Yeah.

Andrew Huberman 15:23 ... well, because I know that a number of people now incorporate, um, so-called HIIT, or high-intensity interval training-

Dr. Andy Galpin 15:28 Yeah.

Andrew Huberman 15:28 ... I think with the hopes of either shortening their workouts-

Dr. Andy Galpin 15:31 Yeah.

Andrew Huberman 15:31 ... and/or, um, gaining some additional cardiovascular benefit. So if we could start with, um, strength and hypertrophy. I know many people want to be stronger. They want to grow larger muscles, or at least maintain what they have.

Dr. Andy Galpin 15:43 Yeah.

Andrew Huberman 15:43 So what are the progressive overload principles, um, that are most effective over time for strength and hypertrophy?

Dr. Andy Galpin 15:51 Yeah, okay. So I'll actually go a little step back. With every one of those categories I talked about, you have what we call your modifiable variables. So this is a very short list of all the things you can modify, the different variables within your workout that can be modified that will change the outcome. A fancy way of saying if you do this differently, then you're going to get a different result. Um, so modifiable variables. Um, the very first one of those is called choice. So this is the exercise choice that you select. Now, one of, um ... I'm gonna go double back here. So I'm kind of doing a little bit of inception, so follow me here as I'm going up a layer to come down a couple layers. Um, I have these fundamental laws of strength and conditioning that, that I'll ... they're kind of like a little bit of a joke. But progressive overload is one of those laws. Another one of those laws is your exercises themselves do not determine adaptations. So here's what I mean. If you're like, "I want to get stronger," you can't select an exercise that doesn't determine you getting strong. If you don't do the exercise correctly, and I'm not even referring to the technique. That, of course, matters. But if you don't execute it in the right fashion, then you're not going to get that adaptation. So if you choose, "I want to get stronger. I'm gonna do a bench press," well, if you do the wrong set range, the wrong repetition range, the wrong speed, you won't get strength. You maybe get muscular endurance and very little strength adaptation. So the exercise selection itself is important, but it does not determine the outcome adaptation. So the very first thing that you need to think about if you're like, "I want to get stronger or add muscle," is not the exercise choice, right? It is the application of the exercise. What are the sets? What are the reps? What are the, uh, rest ranges that you're using? That's going to be your primary determinant. Now, some exercises are certainly better for some adaptations. For example, um, a deadlift is probably not a great exercise to do for long duration endurance. Like, you could theoretically do 30 straight minutes of deadlifting, but it's probably not our best choice, right? It's probably a pretty good choice for strength development, right? Because you're going to do a low repetition, high set range. Um, you could theoretically do bicep curls for power, but probably not your best choice, right? Single joint isolation movement is, is not the best for developing power. If you've ever, ever done a bicep curl as fast as you possibly can, like, that's not going to go well. So in theory, any exercise can produce any adaptation given the execution.... is performed properly. So, now that we've understood that a little bit, the exercise itself does not der- determine the adaptation. Coming within each one of these categories, exercise choice is an important variable, because it does lend you to things like what movement pattern you're in. So in a- other words, if, if you want to get stronger and you're thinking, "Okay, what exercise do I do?" You need to thank- think a little bit about, "What muscle groups do I want to use?" And that's going to be leading you towards the exercise choice. For example, I want to use my quads more. Okay, fine. Maybe you're going to choose more of a front squat type of variation, a goblet squat, so the bar, the load is in front of you. If you want to emphasize maybe more of your hamstrings and glutes, you're going to maybe put a barbell on your back or do a different one. So the exercise choice is important to the prescription because it's going to determine a lot of your success. Okay? Another kind of simpler way to think about this. If you're a beginner, or moderate to intermediate, or maybe you don't have a coach, you probably want to hedge towards an exercise selection that is a little bit easier technically. So you maybe don't want to do a barbell back squat. It's actually a pretty complicated movement. Maybe you want to do a little bit more of, um, again, a goblet squat, or even use some machines, or a split squat, something that's a little bit simpler because you don't have a coach, you're not a professional athlete. The likelihood of success is higher and the risk has now gone lower. So the very first variable within all of these is the exercise choice. The second one is the intensity. And that refers to, in this context, not perceived effort, like, "Wow, that was a really intense workout." It is quite literally either a percentage of your one rep at max or a percentage of your maximal heart rate or VO2 max. So for the strength-based things you want to think about what's the percentage of the maximum weight I could lift one time? And that's, that's what we're going to call one rep max. Or it's a percentage of my heart rate, right? So if I tell you to get on a bike and I want you to do intervals and I want you at 75%, I'm typically referring to 75% of your max heart rate or VO2 max or, you know, something like that. If I tell you to do squats at 75%, that means 75% of the maximum amount of weight you could lift one time, or close.

Andrew Huberman 20:12 Uh, uh, in terms of de- determining what rep max, I confess, um, I've never actually taken the one rep max for any exercise. But I have some internal sense of what that might be, or-

Dr. Andy Galpin 20:22 Yeah.

Andrew Huberman 20:23 ... what range it might be. Is it necessary for people to assess their one repetition maximum before going into these sorts of programs?

Dr. Andy Galpin 20:32 No, not at all. I think a more intuitive way is to take a repetition range. Well, you can do this a couple different ways. So there are, um, equations you can run, and you can just Google these anywhere, and, and these are called conversion charts. And so it says, okay, if I did 75 pounds on my bench press and I did it eight times, you can just run an estimate to say that, okay, you're probably going to be able to bench about 95 pounds for one rep max or something. So that's a very easy conversion chart. So just pick a load that you feel comfortable with, but it's, it's kind of heavy, but not like crazy heavy, and do as many repetitions as you can with a really good technique, and then look what that number would be. So conversion charts-

Andrew Huberman 21:11 Probably safer than doing it one, one repetition maximum.

Dr. Andy Galpin 21:14 For, for the, the general public who has, again, no coaching, it's safer. For a professional athlete, it's not any safer, but, uh, or not even a professional athlete, but a trained person with a coach. But for most people, yeah, that's a good way to go about it. Um, you can also just kind of do it with feel in the sense that, say you want to do a set of five repetitions and you do the load and you think, "I could have done one or two more." And then, then you kind of have an idea of, of what that number's going to be. Um, if you think, "Man, that last one, I had to kind of really, really, really get after it," then maybe just call that that number, right? Um, so you don't have to get overly concerned. In fact, when we start getting into these number ranges, you're going to see that they're all ranges. Uh, we're not going to give a specific 95% for one of these exact reasons. It's not that precise, um, for most of them. In fact, some of them, like hypertrophy, have enormous ranges that you, like, almost can't miss. So the, the intensity in that case doesn't even matter for the most part because that's not the primary determinant. Um, some of these you're going to see intensity as a determinant, and some of these you're going to see volume is the true determinant. Um, so intensity though is, is that second one. Choice was the very first one, uh, manipulable variable. Intensity was the second one. The third one is what we call volume. And so this is just how many reps and how many sets are you doing, right? So if you're going to do three sets of ten, that volume would be 30, right? Five sets of five, that volume is 25. It's just a simple equation, how much work are you totally doing? Uh, the next one past that is called rest intervals. So this is the amount of time you're taking in between typically a set. Um, then from there you have progression, which is what we started to talk about, this progressive overload. Are you increasing by weight, or reps, or rest intervals, or complexity, or whatever? So all of those things, um, can be changed as a method of progression. And so maybe you want to go, um, progressing from a single joint exercise, like a, a leg extension on a machine, and you want to progress by moving to a whole body movement like a squat. That in and of itself, you don't have to change the load, or the reps, or the rest. That is a representation of progressive overload, and it's probably a pretty good place to start, because number one, especially for beginners, you want to make sure that the movement pattern is correct. Don't worry about intensity. Don't worry about rep ranges or any of these things. You need to learn to move correctly, and you need to give your body some time to develop some tissue tolerance so that you're not getting overtly sore. Um, in general, soreness is a terrible proxy for exercise quality. It's a really bad way to estimate whether it was a good or a bad workout, especially for people in that beginner to middle to moderate, in fact even that for our professional athletes. Um, we do not use soreness as a metric of a good workout. Um, it's, it's a really bad idea for a bunch of reasons. On the same token, because stress is required for adaptation, you don't want to leave a gym and feel like, "I don't really do much." Like... (laughs) there has to be there. So if you think about soreness on a scale of one to ten, you probably want to spend most of your time in like the three.

Andrew Huberman 24:16 ... you mean post-exercise.

Dr. Andy Galpin 24:17 Yeah.

Andrew Huberman 24:18 In between workouts.

Dr. Andy Galpin 24:19 Totally.

Andrew Huberman 24:19 And I, uh, I know we'll talk about recovery extensively later but, uh, if one body part or set of body parts is sore, is that an indication that one should stay out of training? I would imagine the answer is no-

Dr. Andy Galpin 24:32 Correct.

Andrew Huberman 24:33 ... uh, in most cases. Um, and secondarily to that, if a particular muscle is sore, does that mean that muscle is not ready to be trained again?

Dr. Andy Galpin 24:42 Yeah. The answer to, to both those is the same, um, which is no, right? Um, you can certainly train a sore muscle. You, you need to, I guess, have a little bit of feel on that, right? So if, if you're sore of like, okay, like and you're moving around a little bit and you're like, "Man, this is a little bit sore," you can train. If you're like, "I can't sit on the couch without crying because my glutes are so sore," like we, we probably don't need to train again, right? We, we-

Andrew Huberman 25:06 Does whimpering count as crying?

Dr. Andy Galpin 25:07 Heck no. (laughs)

Andrew Huberman 25:09 (laughs)

Dr. Andy Galpin 25:09 Yeah. Uh, in that particular case, I'd say you've actually gone to a place of detriment, because now you're going to have to skip a training session, and now you're behind. So your actual total volume, say across the month, is actually going to be lower because you went way too hard in those workouts, had to take too many days off in between. You're gonna see that you're gonna cover less distance over the course of a month or six month or even a year. So you want to walk a pretty fine line and for most people I would say hedge a little bit on the side of less sore than more sore, because frequency is very, very important for almost all these adaptations.

Andrew Huberman 25:43 The training frequency.

Dr. Andy Galpin 25:44 Which is the last modifiable variable, right? Frequency, which is how many times per week are you, are you doing that thing? So those are, um, kind of our, our global things that we can play with. So when I'm trying to manipulate and you can get strength versus hypertrophy, or, you know what? I want like a little bit of both. All those variables are the things that are going through my mind. Which one do I need to move in which direction so that I can get this outcome and not this outcome over here? For example, some folks might want to get stronger but not put muscle mass on. Some folks are just kind of want both, and that's a lot of the general public. I want to get a little stronger and a little bit more muscle, great. But there are instances where people for performance reasons or for purely personal preference, like, "I don't want to get any more muscle." Great. "But I want to get stronger." Awesome. If you manipulate those variables correctly, you can get exactly that, very little development of muscle size and a lot of development of strength, and this is why we continue to break world records in sports like powerlifting and weightlifting that have weight classes. So there's a top number that we can hit in terms of body size, but yet we continue to get stronger and faster. So this is very possible if you understand how to manipulate all those variables. Um, so that being said, we can start off with, you wanted to go strength and then I guess we'll start there.

Andrew Huberman 26:55 Yeah, strength and, and I, I love that you mentioned the fact that it is possible to increase strength without increasing muscle size.

Dr. Andy Galpin 27:01 Yeah.

Andrew Huberman 27:01 At least not dramatically, because I think it's not just weight class athletes. I know a lot of people who, um, for aesthetic reasons, they'd like-

Dr. Andy Galpin 27:08 Right.

Andrew Huberman 27:08 ... to be stronger. They're hearing that having strong bones and strong muscles and tendons, it's great for longevity and for avoiding injury and so many other features of, of life, and, uh, and yet they don't want to f- fill out progressively larger and larger-

Dr. Andy Galpin 27:20 Totally.

Andrew Huberman 27:21 ... uh, sizes of clothing. Um-

Dr. Andy Galpin 27:23 And we can go harder to the mechanisms on that piece if you want, or we can save that and come back to it.

Andrew Huberman 27:27 Sure. Uh, what I'd love to, uh, both, uh,

Andrew Huberman 27:30 what I'd love to know though is if we could define some of these modifiable variables-

Dr. Andy Galpin 27:34 Yep.

Andrew Huberman 27:34 ... in the context of strength. So let's say I was some-

Dr. Andy Galpin 27:37 Oh, okay. Yes. I see what's going on.

Andrew Huberman 27:38 ... was somebody who-

Dr. Andy Galpin 27:38 Yeah.

Andrew Huberman 27:39 ... I come to you and I say, um, and, and let's just say for sake of, of, of balance here, um, 'cause she actually does do some weight training. I bring my sister in, and I say, "Me and my sister both want to get stronger."

Dr. Andy Galpin 27:51 Yep.

Andrew Huberman 27:51 What modifiable variables should, um-

Dr. Andy Galpin 27:54 Okay.

Andrew Huberman 27:54 How should we, uh, modify the variables?

Dr. Andy Galpin 27:55 Love it. All right, great. I'm going to do inception on you one more time. So one of my other laws, this will be fast I promise, of strength and conditioning, is in general the default is all joints through all range of motion. So this is important because it's going to answer your very first question on this strength category. So in general, the ankle should go through the full range of motion in the ankle. The knee should go through the full range of motion in the knee, the hip, the elbow, et cetera, et cetera, right?

Andrew Huberman 28:21 Across the workout, not in a single movement.

Dr. Andy Galpin 28:24 Well, right. (laughs)

Andrew Huberman 28:25 (laughs) I would hope.

Dr. Andy Galpin 28:26 Well-

Andrew Huberman 28:26 Unless there's an amazing exercise I haven't heard about.

Dr. Andy Galpin 28:28 Well, there are some exercises that we're gonna call more full body. Think about a full snatch.

Andrew Huberman 28:33 Mm-hmm.

Dr. Andy Galpin 28:34 Like you're gonna take a lot of your muscles, a lot of your joints through a lot of the range of motions. Um, other ones like an isolation, we call these single joint exercises. So imagine a, a bicep curl. You have one joint in that particular case, the elbow moving. The shoulder and everything else is pretty much stable. And this is how we'll differentiate multi-joint from single joint movements. Um, but yeah, so across, I would even say it doesn't even have to be the day, but maybe throughout the week. Try to get every joint through full range of motion. Now, a couple of quick caveats to that. I am not advocating using full range of motion and allowing really bad exercise technique. So when I say full range of motion, that's the default. That doesn't mean every single person can do that for every single exercise. It means that's where we should be striving to and that's our starting point. You're going to see a lot less injury and a lot more productivity out of your training sessions. In fact, the science is fairly clear on this one. M- strength development as well as hypertrophy is generally enhanced with a larger range of motion of training, um, and the mechanisms are, like, somewhat understood on that. Um, so that being said, if you have to get into, say, a bad r- uh, position with your, say, low back. The spine is a very good one. Your, in general, the spine should stay, it's very neutral, is what we call it. So no, no flexion, no extension, especially in the lumbar region. So if you n- if you're doing a, say, a deadlift, and in order to take your knee through a full range of motion on a deadlift, you have to compromise your back position, that's no bueno. So, caveats there aside, don't kill me. Like, in good positions always.

Andrew Huberman 30:05 And don't kill yourselves-

Dr. Andy Galpin 30:06 Yes.

Andrew Huberman 30:06 ... more importantly. (laughs)

Dr. Andy Galpin 30:08 So why that matters is if we walk through strength, the very first thing I'm going to go through is the, the exercise selection. So let's choose an exercise which ideally has a full range of motion or close to it-... that doesn't induce injury for you, that you can still maintain good neck and s- low back in, in position and everything else, um, you feel comfortable with, so you can feel strong, but you don't feel like, oh my gosh. If you've never snatched before, having you do a snatch for a maximum even, you know, 75%, like it's terrible idea. You're not going to feel confident. It's going to be a train wreck. I would rather put you on a machine bench press so you can go, "I feel stable. I feel safe here, and I can just express my strength." So exercise choice in generally, in general, full range of motion, and you want to kind of balance between the movement areas. So this is an upper body press, so this is pushing away from you, bench press, things like that, upper body pull, pulling an implement towards you, uh, bent row, pull-up. Um, the pressing should be horizontal, so perpendicular to your body, as well as vertical. So this is lifting a weight over top of your head, lifting a weight away from you. The pull version is pulling horizontally to you, and pulling vertically down, pull-up, things like that. Um, for the lower body, we typically call these hinges. I- it's sort of a funny muscle thing that no one's going to laugh at, but like maybe me and you here, is we'll categorize muscles as, or movements, exercises as pushes and pulls, right? So like a squat is, tends to be a push 'cause you're pushing away the ground. A deadlift is a pull 'cause you're pulling the implement up to you. But in reality, every single exercise is only ever a pull, 'cause muscle doesn't push things away. Muscle can only contract and pull on itself. And so again, super nerdy thing that like most people are like, "Yeah," and everyone's like, "That's so dumb."

Andrew Huberman 31:48 No, but I think it's a really important point because it also, um, speaks to something I think we'll get into later, which is that, you know, posterior chain, anterior chain-

Dr. Andy Galpin 31:56 Totally.

Andrew Huberman 31:57 ... um, and if that's, uh, mysterious to people, it'll become clear, uh, before long.

Dr. Andy Galpin 32:00 Yeah.

Andrew Huberman 32:00 Posterior chain, anterior chain, uh, makes a lot of sense to me because of the way it's grounded in the firing of motor neurons, which is ultimately what controls muscle. So it's also I think that-

Dr. Andy Galpin 32:10 You hear it in your nerves all the time.

Andrew Huberman 32:11 Exactly. So it also depends on the lens through which one looks at life and, and exercise. Of course-

Dr. Andy Galpin 32:15 Yeah.

Andrew Huberman 32:15 ... my lens is primarily neuroscience, so.

Dr. Andy Galpin 32:17 Yeah.

Andrew Huberman 32:18 Um-

Dr. Andy Galpin 32:18 So that's-

Andrew Huberman 32:18 But I, but I realized that the importance, I like this idea of, of pushing, um, uh, perpendicular to the body overhead, pulling both toward, uh, toward the body and from overhead. That just makes really good intuitive sense, especially since a lot of people are just listening to this and not watching it.

Dr. Andy Galpin 32:33 Yeah.

Andrew Huberman 32:33 So in your minds, folks, you can think about, um, pushing away like a punch or overhead, um, like lifting something overhead and then pulling toward, uh, your midline, or toward your body rather, and then pulling yourself up like a pull-up in, uh, PE class for those-

Dr. Andy Galpin 32:47 Yeah.

Andrew Huberman 32:48 ... that, uh ?

Dr. Andy Galpin 32:48 So the lower body's the same thing, right? It's some sort of pushing away like a, a squat, or a split squat, or a lunge, or something like that, and then some sort of again we'll call pull or hinge. So a deadlift, or Romanian deadlift, or hamstring curl, or something where you're contracting and calling pulling the thing. And they, and you could split these into like a thousand different categories. If, if you're really in that field, you're going to want to add a bunch of other ones. But that's just like a rough conception. So if you were going to do a single workout, you could choose four exercises, and you could choose one of each, one press, upper body press, one upper body pull, one lower body hinge, one lower body press. And, and that would be like a decently well-rounded exercise. Um, that's your exercise selection. And if you're taking those through your full range of motion, you're at a pretty good spot, or as close as you can. The next one is intensity. So if you want to develop strength, this comes back to one of my favorite scientists of all time who happens to be a nerve guy actually, and generally I like to shit on nerves as much as I possibly can 'cause I'm a muscle guy, but I have to give Henneman some credit here, right? And I know you know who that is.

Andrew Huberman 33:50 Henneman's size principle.

Dr. Andy Galpin 33:51 Yeah. Of course, right? So this is a series of papers I think in the, I think it was in Nature.

Andrew Huberman 33:56 At least some of them, yeah.

Dr. Andy Galpin 33:58 Yeah, in 1954, '56, or like something. You know, you can fact check me. I'm sure you will. Um, but he basically outlined this idea that, okay, um, there is a certain recruitment threshold needed for neurons to fire, and we have muscle fibers in what we call fast twitch muscle fibers and slow twitch muscle fibers. And in general, you're going to activate the slow twitch ones first because they tend to be associated with low threshold motor neurons. It's not exactly that way, but it's, it's close enough, right? Well, the only way that you activate some of these higher threshold neurons is to demand the muscle to produce more force. And it's fairly specific to force, right? It's not something you can do over an endurance thing, right, unless it gets really extreme and fatigue happens. Um, so in general, the only way to use these big chunks of your muscle, which are incredibly important for aging by the way. One of the major problems we have with aging developing, or development of aging-related issues with muscle, is the fact that we lose fast twitch fibers preferentially. And then we have major problems as we go down the line because we've lost a big chunk of our strength and size. So you want to make sure these fibers stay alive and intact. Okay, so if that being said, the only way to develop strength is then to challenge the muscle to produce more total force. If you are fairly untrained or new, I guess I should have stated this all at the beginning as well. One more inception then I'll stop. When it comes to this level of detail of exercise prescription, a, a fairly untrained person is going to respond basically the same to every single thing you do. And in fact we've done this in the lab many times. We've done training studies doing things like 30 minutes of cycling and seeing huge increases in muscle strength and size, which is not a prescription for most people to i- increase size, but people that are really untrained, if you did plyometrics, or strength training, or endurance running, they all just get better at everything. So that caveat kind of aside, if you want to be more intentional and more specific to the s- to the goal of strength, you need to produce more force. Specificity matters, right? So we have size principle to help understand this, and we have our laws of specificity, which say, said principle, right? Specific adaptation to imposed demand. So the adaptation you get, or the result of your training, is going to be a reflection of the demand that you imposed. So if you want to get stronger, you need to impose a demand of strength.... not repetitions. So this has to be, the load has to be very high. Um, in general, you're probably looking at above 85% of your one rep max. If you're moderately trained, maybe 75% will work. Lowly trained, again, everything works. But in general, we want to be pressing a load that's very high. So because the intensity demand is so high, that is going to enforce you to do a low repetition range. You can't do 12 reps at 95%, that, then it wouldn't be 95% of your one rep max. So by definition, true strength training is really going to be in like five repetitions per set or less range. That's where most of it's going to occur for specificity. So we've covered choice, intensity, and, um, repetitions, right? The total amount of sets that you do is, is really kind of up to your personal fitness level, right? Um, if you did as little as like three sets per exercise, that's probably enough.

Andrew Huberman 37:16 Work sets.

Dr. Andy Galpin 37:17 Totally, yeah. Totally work sets, right. So get fully warmed up and build up to that 85%. Don't just walk into the gym and throw 85% on and go, "Thank you." That's a, that's a important distinction. Um, so work your way up, do some, um, like a very classic warmup thing would be like a set of 10 at 50%, a set of eight at 60%, a set of maybe eight again at 70%, and then maybe like a set of five at 75%. So two or three or four sets kind of building intensity and lowering the rep range, and then you would go after your two or three working sets. Um, also, in terms of rest intervals, now because we're trying to, the primary driver of strength is intensity. It's, it's not the volume, right? It's the intensity. So in order to maintain that, we have to do a low repetition range, but in addition, we also have to have a high rest interval. Because if we start to, if we have any amount of fatigue incur, and we have to then either reduce the reps or reduce the intensity, we've lost the primary driver. We've lost that main signal. So the number we're going to throw out typically is like two to four minutes. Um, so imagine you did, you know, your set of bench press, and you did five repetitions at 85%, you probably want to rest two to four minutes before coming back to the bench. That doesn't mean you have to sit there on your phone, like in fact please don't. (laughs) And like everyone will thank you for not doing that, I promise. Um, you can engage other muscle groups. This is what we call super setting. So you're doing your bench press, and while that two-minute clock is running for your chest to rest, you can go over and do your deadlifts. And so, you know, you, you can kind of move back and forth, and this is how you can make strength training a not seven-hour workout. If you're a professional athlete, you're going to take that time, because you want to maximize the outcome. Um, sup-, we've done this actually in our lab too. Super sets will reduce the strength gains, but by a tiny amount.

Andrew Huberman 39:08 Hmm.

Dr. Andy Galpin 39:08 And most of us don't care enough, relative to it's going to triple the length of your training session. It's not worth it. So for the average person, I will tell them, "Yeah, super set." For someone who's trying to break a world record in weightlifting or power lifting, I, don't super set.

Andrew Huberman 39:23 Interesting. Yeah, I think, uh, I've found that, um, I don't recover particularly well from strength and hypertrophy training, so I-

Dr. Andy Galpin 39:30 Like in a workout or the next day?

Andrew Huberman 39:31 Uh, from workout to workout-

Dr. Andy Galpin 39:33 Yeah.

Andrew Huberman 39:33 ... unless I c- keep the total duration of those workouts, I like to say no more than 60 minutes of work-

Dr. Andy Galpin 39:41 Yeah.

Andrew Huberman 39:41 ... of real work.

Dr. Andy Galpin 39:42 Yep, yep.

Andrew Huberman 39:43 Maybe 75. Past 75, I find that I just start to-

Dr. Andy Galpin 39:46 That's a lot.

Andrew Huberman 39:46 ... I have to, I have to introduce additional rest days, or I just get weaker over time.

Dr. Andy Galpin 39:51 Yeah.

Andrew Huberman 39:51 So I, I set a kind of a limit at 50 minutes, and then, um, I usually violate that limit (laughs) and end up doing 60 minutes. So I'm, um, excited to hear that one can super set exercises as long as they work different muscle groups, of course.

Dr. Andy Galpin 40:06 Yeah.

Andrew Huberman 40:07 Right? Um, so I wouldn't want to do like bench press and overhead press super setted, 'cause you're gonna-

Dr. Andy Galpin 40:11 Yeah.

Andrew Huberman 40:11 ... weaken each, uh, I think that just goes without saying for most people, but just to point that out. But that I could, um, do some p- push pull, push pull-

Dr. Andy Galpin 40:19 Yeah.

Andrew Huberman 40:19 ... without compromising total intensity that much.

Dr. Andy Galpin 40:22 Yeah.

Andrew Huberman 40:22 And I, I certainly would be willing to give up a lit- a, a rep here or there, or a, a few, um, pounds here or there. Um, and may I ask whether or not, um, in doing that one gets any even tiny bit or, uh, more of additional benefit in terms of cardiovascular work? Because I imagine after a- a, even a one rep max, which I've never done as I mentioned, but let's say I get three reps on the, uh, overhead press, and then I get, um, four reps on a weighted pull-up-

Dr. Andy Galpin 40:50 Yeah.

Andrew Huberman 40:50 ... and I'm going back and forth, I'm no doubt gonna be breathing harder than if I was sitting there texting away on my phone-

Dr. Andy Galpin 40:56 Yeah.

Andrew Huberman 40:56 ... in between sets.

Dr. Andy Galpin 40:57 Yep, of course. Yeah, and so in fact, in general, one of the things that I'll present in my class is a giant list of, in fact like on the top is all these different exercise adaptations I started the conversation with. And on the, the vertical column are as many of the physiological potential adaptations one would get. So changes in endogenous pH, uh, blood pressure, lymphatic changes, bone density, all these things, right? And just have this giant list. And then you can run a matrix, and you can start to look at, okay, if I do speed training, am I gonna see changes in the nerve- nervous system? Well, like very much so, right? That's the primary actual reason those things work. Very little change in the muscle system. It's almost exclusively explained by the central or peripheral nervous system, right? On that same token, are you gonna expect many cardiovascular adaptations from speed? And the answer is no, because although we didn't cover it, speed is very low intensity, very low rep range, very high rest. Well, as you go to like strength and then you go to hypertrophy, you start seeing more and more increases in cardiovascular adaptations because you're doing exactly that, right? You're starting to reduce stress, and you're starting to increase volume. But you're gonna lose things like bone mineral adaptations, because the load starts to go down. So you can look at this matrix and, and kind of understand if I'm a person who wants to kind of maximize the adaptations I get across my entire physiology for the, uh, least amount of work...... you can choose these different adaptations to go after that are going to kind of land on these things, right? And, and exactly as you mentioned, if you're going to take five minutes' rest between each rep. So let's say the extreme, you're going to do three sets of one repetition for strength at 95%. You're gonna take probably five, maybe seven minutes between each attempt. Like you'd better not expect many like changes in your resting blood pressure. Th- there's no cardiovascular strain there. You're gonna put it together in a circuit where you're gonna lose some potential strength adaptation but you're gonna gain something there. So all these things are ... It's not about good or bad or right or wrong, it's always about what ada- advantage do you want and what disadvantage do you want? And I can cut like really end to the chase here on one of these things, 'cause we'll get to this eventually. If you want to know the ones that are going to generally give you the most physiolodi- logical adaptations across the most categories, you're almost always looking for hypertrophy type of training, and then this, this anaerobic conditioning piece that we'll get into. That's going to hit the most systems at once.

Andrew Huberman 43:20 That's great to know, and we should definitely, uh, go a little bit deeper on those types of, uh, what the modifiable ver- variables are for those categories, 'cause I think that ... I'm guessing the vast majority of people want to be a bit stronger, maybe add some m- a little bit of muscle or more, um, get, make sure their heart is healthy and, uh, et cetera. Um, this is wonderful and, and I think it's clarifying certainly a lot for me. So for strength, let's w- uh, I guess training frequency.

Dr. Andy Galpin 43:47 Frequency. Cool.

Andrew Huberman 43:47 So what should determine training frequency? And

Andrew Huberman 43:50 y- I had the great, uh, benefit of a long time ago when I was in, uh, high school actually, I paid for a, a session over the phone with Mike Mentzer.

Dr. Andy Galpin 43:59 Oh, lovely.

Andrew Huberman 44:00 You know, the Mike Mentzer.

Dr. Andy Galpin 44:01 Sure.

Andrew Huberman 44:01 And we got to be friends, um, over time.

Dr. Andy Galpin 44:03 High intensity training.

Andrew Huberman 44:04 I, at the time I was pretty young and my mother kept saying like, "Why is this like grown man calling the house?" And then we would talk all the time about training, but he tried to convince me to train once every five to seven days, (laughs) uh, very few sets, very high intensity. Um, and I must say, it worked incredibly well.

Dr. Andy Galpin 44:23 Sure.

Andrew Huberman 44:23 It was, uh, I think with my recovery, um, quotient, which was not very good, I think it's improved over time but it was not very good, it was remarkable. But of course this was a time when I was, you know-

Dr. Andy Galpin 44:34 Full of the most animalism you've ever had in your life.

Andrew Huberman 44:36 I was 14. I was, I was sort of on my own version of, of anabolics, right?

Dr. Andy Galpin 44:39 Tear, t- yeah. (laughs)

Andrew Huberman 44:39 I was, I was, you know, really had a ... I had a long arc of puberty, so-

Dr. Andy Galpin 44:41 And you were untrained.

Andrew Huberman 44:43 And I was mostly untrained. I'd been running cross-country-

Dr. Andy Galpin 44:46 So everything was.

Andrew Huberman 44:46 ... and skateboarding and playing soccer, so it w-

Dr. Andy Galpin 44:47 And doing all the things that are like the antithesis of growing muscle.

Andrew Huberman 44:50 Yeah. It was literally, and people will probably say impossible, it was something like 40 pounds of muscle inside of 12 months. It was crazy, and, you know-

Dr. Andy Galpin 44:56 I would believe that.

Andrew Huberman 44:57 But th-

Dr. Andy Galpin 44:57 Yeah.

Andrew Huberman 44:57 But, and so then of course that stopped working over time.

Dr. Andy Galpin 45:01 Sure.

Andrew Huberman 45:01 And then you start going down the, the, um, the odyssey of trying to find the thing that's going to work that well, and you eventually realize that it was because you were untrained, right? Um, so training frequency is, is crucial. Let's say that people are doing these whole body workouts-

Dr. Andy Galpin 45:17 Yeah.

Andrew Huberman 45:17 ... as you've described, and not alternating upper body, lower body, 'cause there's so many different splits that we probably-

Dr. Andy Galpin 45:21 Totally.

Andrew Huberman 45:21 ... it doesn't, probably doesn't make sense to go into, um, splits in, in right now.

Dr. Andy Galpin 45:25 Yeah.

Andrew Huberman 45:25 But how often can, can and should one train a muscle, and how do you know if a muscle is recovered locally, and how do you know if your nervous system is recovered systemically?

Dr. Andy Galpin 45:36 Okay, this is a bunch of really interesting questions. I'm not sure exactly what route you want to go, so I'll, I'll start here. Um, as I mentioned earlier, soreness is not a good barometer of exercise quality, because some types of training are going to induce more soreness and some are going to induce less. That's important to this conversation, because when you ask about how do you know if a muscle is ready to train again, one of the question is well what are you training for? If you're training for hypertrophy, right, muscle size, muscle growth, we need to hedge towards recovery, because what you're trying to do is cause a massive insult there, allow then protein synthesis to occur, building of new tissue which takes time, 48 to 72 hours like kind of at a minimum, that process needs to occur. If you're doing actually more strength, and this is a differentiation between hypertrophy and strength, then you didn't induce actually much damage. In fact, you're generally not going to get very sore from true strength training, very little, unless you get r- really heavy, you did it a lot. The primary driver of hypertrophy is not the same primary driver of strength. We talked about that already. That's intensity driven. It, for vol- i- for hypertrophy it's not intensity. So because we have different mechanisms, we have different outcomes, even though they're closely aligned. Strength is not going to cause a lot of soreness. Therefore, intensity is the driver, therefore frequency can be as high as you want. So you can train every single day the same exact muscle if speed or power or strength are the primary training, training tools, because you need stimulus. There is skill is, skill as well, right? Practice. That, you know that as much as anybody. Developing a new motor pattern requires a lot of repetitions, right? You don't need a tremendous amount of rest. That's not ... It's n- it's not a damage thing, right? It's a repatterning issue. So strength training, in fact if you look at again true strength professional athletes, they're going to train the same muscles basically every day.

Andrew Huberman 47:27 Wow.

Dr. Andy Galpin 47:28 They're gonna squat every day.

Andrew Huberman 47:29 And, and is that because the, the primary mode of adaptation is recruitment of these high threshold motor units? It's, so it's mainly neural?

Dr. Andy Galpin 47:36 Uh, no. So everyone's gonna say that, and this is where I get all feisty.

Andrew Huberman 47:40 Well I'm not saying that.

Dr. Andy Galpin 47:41 (laughs)

Andrew Huberman 47:41 That was actually ... There was a question mark there.

Dr. Andy Galpin 47:43 Okay. (laughs) Okay.

Andrew Huberman 47:44 If we, if we were online putting comments, we, there'd be a question mark.

Dr. Andy Galpin 47:47 We would've f- we would've fought.

Andrew Huberman 47:47 Right. Would've.

Dr. Andy Galpin 47:48 I would've blocked you.

Andrew Huberman 47:49 (laughs)

Dr. Andy Galpin 47:49 I was just kidding. That's how-

Andrew Huberman 47:50 I think you already blocked me.

Dr. Andy Galpin 47:51 I-

Andrew Huberman 47:51 No.

Dr. Andy Galpin 47:51 Probably twice.

Andrew Huberman 47:53 (laughs)

Dr. Andy Galpin 47:53 Um, okay. The early adaptations to exercise, especially strength training, are hedged towards the nervous system, no question about it. People always say central nervous system, but it's probably more peripheral, right? Whatever. Semantics probably, but pedantic. It's nerve- Um, if you train today, tomorrow morning you're not gonna wake up with a actually increase in contractile proteins in muscle. Your muscle might be a little bit bigger due to some acute swelling, but you could have an in- uh, uh and pretty acute that-... persists, change in, in the nervous system we'll call it, that allows you to be stronger like within a couple of days. Sustained hypertrophy is probably more along the lines of four weeks where we can see that, right? We can actually see changes like in the ultrasound. Now you're making changes immediately. That protein synthesis process is happening like very fast, and it's gonna last... It just takes us time to measure it in terms of a noticeable change in your whole muscle size. So that being said, the first four weeks we typically say are primarily, um, nervous system. After that now we're seeing- starting to see most of the changes coming from the muscle side of the equation. So with strength development it's a combination of three areas. In fact all muscle contraction has these same three things. It starts off with some signal, right, from somewhere in the body, whether that's all the way up at the top or at the level of the spine depending on if this is a reaction or an actual conscious control. From there that some signal has to tell the muscle to contract, okay? So signal is one. Two, it's muscular contraction. And there's a lot of variables inside the muscle tissue itself that determine its functionality. And so if we took an individual biopsy and took a muscle fiber from you and took one from me and we took those muscles out and put them in a Petri dish, and I tied one end to a force transducer, the other end to a thing that pulls it, and we soaked it in a bath of calcium and a bunch of other stuff, even if they were the same size, your fibers might contract a lot faster than mine, even relative to size. Um, or not, or slower, or there's various properties. And so the intrinsic fibers themselves determine a lot of functionality. From there, muscle fibers don't cause movements. Muscle fibers simply contract. They're all surrounded with connective tissue, and that's all surrounded with a bunch of more connective tissue, and that all surrounds into a muscle. That muscle is then surrounded with more connective tissue. That all comes together into a giant tendon. That tendon attaches to the bone. It's the pulling on those tendon that actually move the bone that cause human movement. So that's area three. Area one, the nervous system. Area two, the muscle contraction. Area three, some sort of connective tissue thing. Changes happen at all three of those levels. And we're not even now talking... We haven't even entered the discussion of biomechanics and you changed say the pennation angle of the muscle, which is the angle at which the muscle fibers lay relative to the bone. Right? So this is basic mechanics. Is it pulling perpendicular to the bone? Is it pulling horizontal to the bone or some sort of angle? All of these things determine human performance. So when you're talking about, again, that strength development, you can see tremendous improvements in total force production by manipulating all of those areas and you have not touched changes in muscle size. If you change muscle size in a true sustained fashion, whether this is sarcoplasmic or contractile proteins, you have given yourself more opportunity to produce more force. It doesn't guarantee you produce more force. Um, bodybuilders are not stronger than power lifters even though they have more muscle. But bodybuilders are probably stronger than most people. So there is a relationship between muscle size and strength. It's n- it's not a one-to-one guaranteed ratio, and that's generally because the... although the muscle has been aided, they may have not changed the biomechanical considerations. They have... may have not changed the connective tissue nor the nervous system stuff. And so that's why we see this giant relationship, that R value is pretty high between strength and hypertrophy, but if you really want to get to the ends of it, it's not. And that matters to your actual question 10 minutes ago, because again you can train strength daily on the same muscle. But if you want to allow for that process of connect- uh, contractile proteins to- to add and grow, then you're going to have to allow some recovery. Because if you go back into that muscle too soon, you're gonna blunt the response. You're gonna stop it. You're gonna cut it off. You have all kinds of- of problems going on in the cell that are gonna, um, just attenuate that- that growth response. So I gave you the answer for strength training. The answer for hypertrophy is probably less than three out of 10 on level of soreness, you can go again. In general you're probably looking at 72 hours is th- the optimal window. So if you trained your- your shoulders on Monday, you probably wouldn't want to train them again on Tuesday if hypertrophy is the goal. Maybe Wednesday, maybe Thursday is best. So something like an every two to three day window is- is probably, um... And we know a little bit more now about why that is. Um, the gene cascade, the signaling response happens... Well the signaling happens instantaneously, right? Within seconds. The gene cascade is probably in the peaked in the four hour window, like dep- depending on which gene you want to look at. But it's just kind of a snapshot. But the protein synthesis process is 24 to 48 hour thing, and so it tends to kind of look like let that thing finish and let that signal go back to baseline and then hit it again, and then hit it again. And now as long as you're providing the nutrients, the recovery should happen and you should be able to sustain the same work output in the training session so the stimulus stays high and the recovery is there and you can now continue to grow muscle.

Andrew Huberman 53:26 You mentioned 48 to 72 hours for hypertrophy. What if be- for re- wha- whatever reasons, uh, the- the training split, uh, lifestyle factors, et cetera, somebody say, let's use your example, trains, uh, shoulders on Monday. Um, ideally they would train them again on Thursday-

Dr. Andy Galpin 53:46 Yeah.

Andrew Huberman 53:46 ... in their particular instance. Somewhere Wednesday or Thursday. But they don't. They wait until Saturday or Sunday for whatever reason. Maybe it's more compatible with their work- work and other exercise schedule. Whatever the reason, are they actually losing hypertrophy that they gained or they've missed o- uh, a window to induce further hypertrophy?

Dr. Andy Galpin 54:06 It's probably better to think about it th- the latter. It's not that you're- you've lost, it's just you've just kind of lost an opportunity to- to make more progress. Um, I will save you a little bit, and kind of going back to your HIT program. This is the original high intensity training, the- the Menser thing, right? Which is not...

Andrew Huberman 54:24 The HIT with one I. Not the high intensity interval training but high intensity training.

Dr. Andy Galpin 54:28 Correct.

Andrew Huberman 54:28 Like one set to absolute failure-

Dr. Andy Galpin 54:30 Totally.

Andrew Huberman 54:30 ... maybe two for each muscle group.

Dr. Andy Galpin 54:34 ... 20-minute workouts-

Andrew Huberman 54:35 ... dividing your body into three, into a three-way split, and then literally training like-

Dr. Andy Galpin 54:38 Smashing.

Andrew Huberman 54:39 ... six times a month. Which most people would think that is absolutely crazy.

Dr. Andy Galpin 54:43 Yeah.

Andrew Huberman 54:43 There's no way that's gonna work. And I can tell you-

Dr. Andy Galpin 54:45 It does.

Andrew Huberman 54:45 ... if you are untrained, you, you grow like a weed.

Dr. Andy Galpin 54:48 Just-

Andrew Huberman 54:48 If you train hard enough and-

Dr. Andy Galpin 54:49 Even if you're trained.

Andrew Huberman 54:50 ... you rest hard. Yeah.

Dr. Andy Galpin 54:50 Look at the people who Mike trained. He put a lot of bodybuilders on really high levels. Now, they had the same similar help you had (laughs) at that timeframe.

Andrew Huberman 54:59 Well wait, to be very clear, I was not taking-

Dr. Andy Galpin 55:00 (laughs)

Andrew Huberman 55:00 ... exogenous in a box. In fact, I will-

Dr. Andy Galpin 55:02 No, but your endogenous was just as good.

Andrew Huberman 55:03 I, I probably was. I wasn't measuring my levels there, but I probably would. I grew easy-

Dr. Andy Galpin 55:07 Yeah.

Andrew Huberman 55:07 And gen- in general, I tend to grow pretty easily, um, from weight training. But the, uh, but, and I should say that to Mike's credit, and I think this is an important message, that he was the one who really said, "Look, un- unless you're gonna make a professional career out of it-"

Dr. Andy Galpin 55:24 Yeah.

Andrew Huberman 55:24 "... do not run the health hazards of exogenous hormones. It, you know-"

Dr. Andy Galpin 55:28 Oh.

Andrew Huberman 55:28 "... certainly not at your age." So he deterred me from that, which was great, because it never entered my mind. It just was one of those things where-

Dr. Andy Galpin 55:33 Yeah.

Andrew Huberman 55:34 ... Mike Mentzer said, "Don't do it," and he had clearly done it, right?

Dr. Andy Galpin 55:37 Honestly.

Andrew Huberman 55:37 And so he's speaking from an informed place. It never entered my mind. But also, I was r- what was really wild is I was continuing to run across country. Um, and so there was a, there was a, um, trade-off there at some point.

Dr. Andy Galpin 55:49 A little bit of an interference. Yeah.

Andrew Huberman 55:50 But when you're young, you can get, m- many people can get away with-

Dr. Andy Galpin 55:53 Totally.

Andrew Huberman 55:53 ... with what at this age would surely place me into a state of overtraining, even at low volume. We'll see.

Dr. Andy Galpin 55:58 Yeah. Well, I mean, like, the, the whole field on interference effect has changed quite a bit, uh, recently, which we could come back to if you want. Um, but just to, to finish out the, the idea here with that last question, um, if you wanna take five days or six days in between each muscle group, you can do that. In fact, if you look at the research, it's gonna show that frequency is not that important. It, it, well, it's not that it's unimportant, but it's, it can handle changes as long as you get to the same total volume. So you can do that. You just have to do a lot more work in that one workout. If you care about the six-week, eight-week thing. If you're like, "I'm in this for the next 60 years," like, it's probably okay, right? Um, but it can be there. The, the challenge with splitting up your training sessions for hypertrophy into smaller numbers, like once or twice a week, it's just difficult to get that number. It's typical to get that volume done.

Andrew Huberman 56:54 Mm-hmm.

Dr. Andy Galpin 56:55 Um, volume-wise, the more recent meta-analyses are gonna say that you're probably looking at around 10 working sets per muscle group per week. Seems to be kind of the minimum threshold that you're gonna want to hit. So if you did three sets of 10 at your shoulders on Monday, three sets of 10 shoulders Wednesday, and three on Friday, that's nine working sets. If you wanted to do just three different shoulder work, uh, exercises on Monday and hit your nine sets, it's not really actually gonna be that much different. The problem is ten is kind of the minimum. You probably want to look for more like 15 to 20, and in fact, well-trained folks, 20, 25. That becomes very challenging in one workout. In fact, defuncto, you're not gonna be able to do it, right? And so that is where it's not the frequency that looks like it kills you, it's just the fact you have got to get, because the total driver of strength is intensity, but the total driver of hypertrophy is volume, assumed you're taking it to fatigue, right, or muscular failure. So it's just tough to get enough done. If you can, um, and if you want to set your schedule up that way, like, you probably remember, if you do those types of training sessions where you're just gonna completely exhaust a muscle, it's gonna be ti- it's gonna be sore for a while. You're, you're, you're probably not going to come back. And that's sort of the logic behind that, was let's take this thing to tremendous failure and give it six days to recover. Um, it can work, it's just not the best, I think is one way to think about it.

Andrew Huberman 58:19 Yeah.

Dr. Andy Galpin 58:19 For most people.

Andrew Huberman 58:20 It's also hard to do those workouts without a training partner, if you really want to do them correctly.

Dr. Andy Galpin 58:23 And stimulants and headphones and (laughs) all kinds of other things, right?

Andrew Huberman 58:26 Yeah. Mi- well, anyway, the, yeah, stimulants are not, uh, don't, certainly don't recommend those. Um...

Dr. Andy Galpin 58:31 Yeah.

Andrew Huberman 58:31 It, maybe a cup of coffee or two, if that's your thing. But, um, and maybe some of the safer supplements, but certainly not-

Dr. Andy Galpin 58:39 Yeah.

Andrew Huberman 58:39 ... sorts of stimulants that the guys in the '70s and '80s were famous for taking.

Dr. Andy Galpin 58:42 No way, or still use.

Andrew Huberman 58:43 Or still use. Um, you talked about

Andrew Huberman 58:45 repetition ranges broadly for strength training, so five or less.

Dr. Andy Galpin 58:48 Yep.

Andrew Huberman 58:49 You said frequency could be as often as every day.

Dr. Andy Galpin 58:51 Yeah.

Andrew Huberman 58:52 Rest two to four minutes, maybe even longer if you're going for one repetition maximum.

Dr. Andy Galpin 58:57 Yeah.

Andrew Huberman 58:57 For hypertrophy-

Dr. Andy Galpin 58:58 Sure.

Andrew Huberman 58:59 ... what are the repetition ranges that are effective, and what are the ones that are most effective if one is trying to maximize some of the other variables? Like, people don't want to spend more than-

Dr. Andy Galpin 59:09 Yeah.

Andrew Huberman 59:09 ... an hour to 75 minutes-

Dr. Andy Galpin 59:11 Realistic.

Andrew Huberman 59:11 ... in the gym. Because I think that, uh, while the rep ranges might be quite broad, as you alluded to earlier, there's the practical, there are the practical constraints.

Dr. Andy Galpin 59:20 Yeah.

Andrew Huberman 59:20 So what a- what repetition ranges or percent of r- one repetition maximum, um, should people consider when thinking about hypertrophy?

Dr. Andy Galpin 59:28 Right. Um, the quick answer there is anywhere between, like, five to 30 reps per set. That's gonna show across literature pretty much equal hypertrophy gains. Um, and we could have a really interesting discussion about why that is, but I'm just remembering one thing from a second ago. I want to give a better answer for the frequency. You can do every single week for strength, or every single day for strength. If you want though, like, what's probably minimally viable, two. Twice per week per muscle. So hamstrings, strength, twice per week. That, that's a good number to get most people really strong.

Andrew Huberman 1:00:00 Okay.

Dr. Andy Galpin 1:00:00 You can do every single day. You don't need to, though. So I, I want to make sure that, like, I wasn't saying you have to train a muscle 85% every single day to get it strong. Two is a good number. Three is great, but probably even two is really effective.

Andrew Huberman 1:00:12 Got it. And this explains the, the high frequency of, of training for strength athletes. That's always mystified me. Um...

Dr. Andy Galpin 1:00:18 Yeah.

Andrew Huberman 1:00:19 And the very long workouts make sense, because very long rest-

Dr. Andy Galpin 1:00:21 They're gonna even train twice a day.

Andrew Huberman 1:00:22 Wow.

Dr. Andy Galpin 1:00:22 Like, even though it's a squat in the morning, squat in the afternoon every day.

Andrew Huberman 1:00:25 With their eating and their sleeping, they probably don't have time for anything else.

Dr. Andy Galpin 1:00:27 Well, that's why they're pros. So that's their job, right? That's what they do. Um, so yeah, right, hypertrophy. Um, strength training programming is...... somewhat complicated, right? Because of, that's not the danger, but you're going to have to pay one way or the other, right? The risk is a little bit higher 'cause the load's higher and you have to be a little bit more technically proficient. When it comes to hypertrophy training, the way I like to explain it is, it's kind of idiot proof. The programming is idiot proof, the work is hard though. So, here, here's your range, anywhere between, th- you know, five reps and 30. Can you hit somewhere in there? Perfect. It's all equally effective. You can't screw that up. The only caveat for hypertrophy is you have to take it to muscular failure.

Andrew Huberman 1:01:10 And you need enough rest for the adaptation and protein synthesis to occur.

Dr. Andy Galpin 1:01:14 Yep.

Andrew Huberman 1:01:14 Yeah.

Dr. Andy Galpin 1:01:14 Right, and if you recover faster, you can maybe do it more frequently, and if you don't, maybe less frequently.

Andrew Huberman 1:01:19 Hmm. By that logic, should people perhaps experiment and figure out what repetition range allows them to recover, um, in concert with the training frequency that they can do consistently?

Dr. Andy Galpin 1:01:30 My recommendation is I think you should actually set your, uh, use the repetition range as a way to have some variation, because most people don't want to go in the gym and do three sets of 10. They're going to get very bored very quickly. And so I, I think you should actually intentionally change the rep schemes for simple sake of having more fun. It is a very different challenge. The mechanisms that are inducing hypertrophy are different, but there's only a maximal amount of growth that one can get, right? And so you have, as best we think it now, and, and some people actually will espouse that we know really clearly about the mechanisms of muscle hypertrophy. We don't. It, it's still very much a guessing game, but the three most likely drivers are one, metabolic stress, two, mechanical tension, and then three, muscular damage. You don't have to have all three. One is sufficient. You can have a little bit of one or two, and you can kind of... So you get it to play here. We've already talked about the muscular damage. Again, it's very clear, more damage is not better, but it is somewhat a decent proxy, right? Like again, a little bit of soreness is good. Just don't get so sore it's compromising your total volume. All right? Uh, mechanical tension is kind of like strength. This is why if you do even sets of five or eight, and you're kind of close to that strength range, you will gain a little bit of muscle. It's not optimal muscle gain, but you're going to gain some because everything in these, like physiology doesn't cut off at four reps and then five reps is a different thing, right? It's, it's always a blend. So think of it as like a, a fading curve. As you get closer to the end, it fades less effective. As you get closer to the middle, it's more effective. Anywhere between eight reps per set to 30, it's equally effective. Past 30, it's going to blend out. Past eight to five to four to three, it's going to blend, you know, lesser there. So metabolic stress is one. The damage is the other. Or sorry, mechanical tension is the one that's heavy. Muscle damage is the other one. The third one is metabolic stress. And this is, um, a- again, a bit of an area of scientific contention, but something's there. I know something's there. We just, we're just kind of fumbling to figure out what exactly it is. And this is, metabolic stress is the burn, right? It, it's there. Um, it's why blood flow restriction training probably works. That's done very light, so there's no mechanical tension, there's very little damage, but somehow it induces a good amount of hypertrophy.

Andrew Huberman 1:03:46 Very painful.

Dr. Andy Galpin 1:03:47 Oh, boy.

Andrew Huberman 1:03:48 I tried this, uh, I have a friend, former special operator who, um, lives out on the east coast and took me through a blood flow restriction, um, training protocol in a park.

Dr. Andy Galpin 1:03:58 Yeah.

Andrew Huberman 1:03:58 And I, I don't think I, I actually cried.

Dr. Andy Galpin 1:04:01 (laughs)

Andrew Huberman 1:04:02 But, um...

Dr. Andy Galpin 1:04:02 You probably did.

Andrew Huberman 1:04:03 But I might have cried out once or twice. It was unbelievable, especially the lower body movements.

Dr. Andy Galpin 1:04:09 Yeah.

Andrew Huberman 1:04:09 Um, now it was a humid day. I'll claim a little bit of jet lag.

Dr. Andy Galpin 1:04:13 No.

Andrew Huberman 1:04:13 But-

Dr. Andy Galpin 1:04:13 No.

Andrew Huberman 1:04:13 ... it was brutal. It was really brutal. And I also-

Dr. Andy Galpin 1:04:16 Do it on the best day of your life and it's still brutal.

Andrew Huberman 1:04:17 Okay. Well-

Dr. Andy Galpin 1:04:18 Still brutal.

Andrew Huberman 1:04:18 ... that makes me feel a little bit better. It was intense. I, and um-

Dr. Andy Galpin 1:04:22 Yeah.

Andrew Huberman 1:04:22 ... and I, and people should know that it, it is important to use the proper cuffs for these things. I don't have any, uh, relationship to any of the companies that sell these cuffs, but the reason is that you actually need to block particular avenues of blood flow. You can't simply cinch off a muscle. You can't tourniquet a muscle and train.

Dr. Andy Galpin 1:04:36 Not a good idea.

Andrew Huberman 1:04:37 You can actually, uh, kill yourself that way.

Dr. Andy Galpin 1:04:38 Yeah, you can get a blood clot.

Andrew Huberman 1:04:39 Yeah. And, um, so if you're interested in blood flow restriction training, uh, I imagine you have some content about this or will at some point, but also there, there are resources online that people can look up.

Dr. Andy Galpin 1:04:49 Yeah, yeah.

Andrew Huberman 1:04:50 Uh, a question about hypertrophy training that I think, um, many people are wondering about. Train to failure or don't train to failure? Assuming good form.

Dr. Andy Galpin 1:05:00 Yeah, okay. Assuming good form. Great. Um, the answer is both. So you want to train to failure, but you don't need to go to extreme failure. So you don't need to necessarily go to that, like, a partner has to lift the barbell off my chest. But you have to get close. You have to drive either heavy, stress, damage, right? Or, or pump. And so a really easy, practical way to think about this, um, I heard Mike Israetel, who runs a company called Renaissance Periodization years ago outline this at a NSCA talk. And it was beautiful and I thought this is the most eloquent way to explain the context about training for hypertrophy. So only look for three things in your workout. And let's say that you want a particular muscle to grow. Uh, let's say you want your glutes to get larger. Okay, when you're doing your glute exercises, number one, are you feeling the glute contract? Okay, it doesn't have to be there, but that's a good sign if it is. Okay, let's say I didn't really feel my glute contract. I felt it more in my quads or my back. Okay. Did you feel a big pump afterwards? No, I didn't really feel a pump there eitherwards or during. Okay, great. Number th- three, next day, did you feel a little bit of soreness there at all? No, I didn't. Well, that's a very good indication you didn't feel it during the workout, you felt no sort of pump and it didn't get sore, don't expect much growth. Didn't happen.

Andrew Huberman 1:06:17 You distributed the work across a bunch of muscle groups.

Dr. Andy Galpin 1:06:20 Most likely other muscle groups were too involved, right? Especially if you're like, "No, but man, my back got really sore." Well, that's a really good indication of telling you what the hell was moving.

Andrew Huberman 1:06:29 Mm-hmm.

Dr. Andy Galpin 1:06:30 And so in terms of targets, if you were to put, again, a one to, you know, 10 scale, how much should I feel it burning during? Anything less than a three...Okay, it's probably not doing much, right? But it doesn't, like seven is not, a 10 is not better than seven. You need to feel it, but it doesn't have to be like, "Oh my gosh, I'm dying here." Uh, soreness, same barometer, right? So if you can get like three, three and three, you're probably in a pretty good spot. Five, five and five is maybe better, but you don't need to go much past that. So I want you to feel the muscle group either working or if you're like, "I didn't feel it much. I didn't really get a pump, but the next day it got really sore," well then you're, you're still, you know, on a good path. Um, again, really sore as in like, "Ooh, a little tender, but next day it's okay. Day after that I could, I could train no problem." That's really what you want to go after, and in terms of understanding is this likely to produce some growth or not?

Andrew Huberman 1:07:23 Excellent, excellent, very clear parameters and recommendations I know are benefiting me and will benefit a lot of people. If you'd be willing to throw out a few sort of sets and rep parameters that could, uh, act as broad guidelines-

Dr. Andy Galpin 1:07:36 Yeah.

Andrew Huberman 1:07:37 ... for people who want to, uh, explore further. Uh, I realize that with all these modifiable variables that there's no one size fits all for strength. I love this 5 to 30 for hypertrophy.

Dr. Andy Galpin 1:07:49 Yeah. (laughs)

Andrew Huberman 1:07:49 That's pretty brutal thing. I don't think I've ever done a 30 rep set of anything, but, but now that you've thrown that out there, I see it as a bit of a challenge.

Dr. Andy Galpin 1:07:54 You want to know what's awesome about 30? You're going to get an insane pump. You're gonna burn like crazy, but you won't get super sore. 'Cause the mechanical tension's so l- so low, it's so light. So you, you can, you can get away with those things and you, it's hard because your mind is going to wander. You're gonna get at like rep 20 and you're gonna be like, "I'm done." And you're like, "No, there's, there's a lot left here to get to 30." Where like a set of 10 is, is much easier. Like you're just like, "Okay, two more, two more." Set of 30 is like, "I got 16 more." (laughs) It's awful, but you're not going to-

Andrew Huberman 1:08:21 Just the counting is work.

Dr. Andy Galpin 1:08:22 It's ter- terrible, right?

Andrew Huberman 1:08:23 Yeah.

Dr. Andy Galpin 1:08:23 And people tend to just kind of like check out. So 30 is possible, but a little bit extreme, extreme. Um, but I would recommend 'em, all of them. Like it's a really fun play. You can do different in the same workout too, by the way. Like you could do one set of 10, uh, pushups and then take a little break and then do a set of 25. You can, you can mix and match these things. Um, there's no magic recipe that has to happen, uh, for all those. Or do it different. So Mondays are my sets of 10 days, Wednesdays are my set of 20 days, and Fridays

Dr. Andy Galpin 1:08:50 are my set of 30 days. And you can have all kinds of fun there and it's hard to screw up.

Andrew Huberman 1:08:54 Great. I lo- that phrase is always reassuring. (laughs) So for strength, is there a, um, sets and reps protocol that-

Dr. Andy Galpin 1:09:02 Yeah.

Andrew Huberman 1:09:02 ... that is, um, pretty surefire?

Dr. Andy Galpin 1:09:04 So a way to, to just think about a really fast answer for power, well speed, power and strength, is what I just call the three to five concept, right? So pick three to five exercises. If you're feeling better that day, choose on the higher end. If you're feeling less that day or you have a shorter timeframe to train, go less. So this would be three sets or three exercises rather, or five exercises the most. So three to five exercises. Do three to five reps, three to five sets. Take three to five minutes rest in between, and do it three to five times a week. So that can be as little as three sets of three for three exercises, three times a week. That's, that's a 20 minute workout three times a week. It can be as high as five sets of five for five exercises five days a week. So it's very broad and allows people to still stay within the domains of strength and power while still being able to move and contour toward their lifestyle and, and soreness and time and all those things. The only differentiator to pay attention to between power and strength is intensity. So if you want strength, this is now 85% plus of your max, right? If you want power, it needs to be a lot lighter, 'cause you need to move more towards the velocity end of the spectrum, because power is strength multiplied by speed. So while getting stronger, by definition can help power, you probably want to spend more of your time in the 40% to 70% range, like plus or minus. So that's it. Both of them conceptually though work, everything else, the exercise, the reps, the, the frequency, all that can be still in the three to five range. Just change the intensity depending on which outcome you want.

Andrew Huberman 1:10:45 The nervous system obviously plays an important role at the level

Andrew Huberman 1:10:48 of nerves controlling the contraction of muscle fibers. But of course we have these upper motor neurons, which are the ones that reside in our brain that control the lower motor neurons that control muscle.

Dr. Andy Galpin 1:10:57 Yeah.

Andrew Huberman 1:10:58 And this takes us into the realm of where the mind is at during a particular movement. And to me, this is not an abstract thing. I can imagine doing workouts that are mainly focused on strength or mainly focused on hypertrophy. And in the case of strength, am I trying to move weights? And when I'm t- trying to generate hypertrophy, am I trying to, quote unquote, challenge muscles? In other words-

Dr. Andy Galpin 1:11:25 Yeah.

Andrew Huberman 1:11:25 ... if I am just trying to move a weight away from my body, you know, push- pushing a bench press or an overhead press, I don't know that I want my mind thinking about the contraction of my medial delts.

Dr. Andy Galpin 1:11:36 (laughs)

Andrew Huberman 1:11:36 I think I want my mind in getting the weight overhead with the best p- proper form. Best, excuse me, and proper form. And certainly with hypertrophy training, best and proper form is going to be the target as well. But that simple s- or I should say subtle mental shift changes the patterns of nerve fiber recruitment. So can we say to get stronger focus on moving weights, still with proper form and safely, and to get hypertrophy focus on challenging muscles still with proper form and safely?

Dr. Andy Galpin 1:12:10 It's very fair. Yeah, as a, as a snapshot answer, it is