Essentials: Build Muscle Size, Increase Strength & Improve Recovery

0:00Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science -based tools for mental health, physical health, and performance. I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is 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. Today I want to talk about something that is vitally important for not just athletic performance, but for your entire life and indeed for your longevity, and that's muscle.

0:40And one of the things that's exquisite and fantastic about the human brain is that it can direct all sorts of different kinds of movement, different speeds of movement, movement of different durations. All of that is governed by the relationship between the nervous system neurons and their connections to muscle. So today, as always, we're going to talk a little bit of mechanism. I'm going to explain how neurons control muscle. We will touch on some nutritional themes and how that relates to muscle in particular, a specific amino acid that if it's available in your bloodstream frequently enough, and at sufficient levels can help you build a muscle.

1:22So let's talk about muscle and improve the quality of muscle. We are also going to talk about recovery. That's when muscle grows, that's when muscle gets more flexible. None of that actually happens during training. It happens after training. Most people, when they hear the word muscle, they just think about strength. But of course, muscles are involved in everything that we do. They are involved in speaking. They are involved in sitting and standing up. They are involved in lifting objects, including ourselves. They are absolutely essential for maintaining how we breathe. They are absolutely essential for ambulation, for moving, and for skills of any kind.

2:02So when we think about muscle, we don't just want to think about muscle, the meat that is muscle, but what controls that muscle and no surprise what controls muscle is the nervous system. The nervous system does that through three main nodes of control. Basically, we have upper motor neurons in our motor cortex. So those are in our skull, and those are involved in deliberate movement. Those upper motor neurons send signals down to my spinal cord where there are two categories of neurons. One are the lower motor neurons, and those lower motor neurons send little wires that we call axons out to our muscles and cause those muscles to contract.

2:43They do that by dumping chemicals onto the muscle. In fact, the chemical is acetylcholine. Now there's another category of neurons in the spinal cord called central pattern generators or CPGs, and those are involved in rhythmic movements. Anytime we're walking or doing something where we don't have to think about it to do it deliberately, it's just happening reflexively that central pattern generators and motor neurons. Anytime we're doing something deliberately that the top down control, as we call it, from the upper motor neurons comes in and takes control of that system. So it's really simple.

3:16You've only got three ingredients. You've got the upper motor neurons, the lower motor neurons, and for rhythmic movements that are reflexive, you've also got the central pattern generators. I'd like to take a quick break and acknowledge our sponsor, 8 -Sleep. 8 -Sleep makes smart mattress covers with cooling, heating, and sleep tracking capacity. I've spoken before on this podcast about the critical need for us to get adequate amounts of quality sleep each and every night. Now one of the best ways to ensure a great night's sleep is to ensure that the temperature of your sleeping environment is correct.

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4:46Again, that's 8 -Sleep .com slash Huberman to save up to $350 off your Pod4 Ultra. Today's episode is also brought to us by Element. Element is an electrolyte drink that has everything you need, but nothing you don't. That means the electrolytes, sodium, magnesium, and potassium, all in the correct ratios, but no sugar. Proper hydration is critical for optimal brain and body function. Even a slight degree of dehydration can diminish cognitive and physical performance. It's also important that you get adequate electrolytes. The electrolytes, sodium, magnesium, and potassium, are vital for the functioning of all the cells in your body, especially your neurons or your nerve cells.

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5:58Again, that's drinkelement .com slash Huberman to claim a free sample pack. I now like to shift our attention to how to use specific aspects of muscular contraction to improve muscle hypertrophy, muscle growth, as well as improving muscle strength. There are a lot of reasons to want to get stronger, and I should just mention that it's not always the case that getting stronger involves muscles getting bigger. There are ways for muscles to get stronger without getting bigger. However, increasing the size of a muscle almost inevitably increases the strength of that muscle, at least to some degree.

6:35The reasons why most everyone should want to get their muscle stronger is that muscles are generally getting progressively weaker across the lifespan. When I say getting stronger, it's not necessarily about being able to move increasing amounts of weight in the gym, but rather to offset some of the normal decline in strength and posture and the ability to generate a large range of movement safely that occurs as we age. There's an important principle of muscle physiology called the Heneman Size Principle. The Heneman Size Principle essentially says that we recruit what are called motor units. Motor units are just the connections between nerve and muscle from a pattern that staircases from low threshold to high threshold.

7:26What this means is when you pick up something that is light, you're going to use the minimum amount of nerve to muscle energy in order to move that thing. Likewise, when you pick up an object that's heavy, you're going to use the minimum amount of nerve to muscle connectivity and energy in order to move that object. So it's basically a conservation of energy principle. Now, if you continue to exert effort of movement, what will happen is you will tend to recruit more and more motor units with time. As you recruit more and more of these motor units, these connections between these lower motor neurons and muscle, that's when you start to get changes in the muscle.

8:11That's when you open the gate for the potential for the muscles to get stronger and to get larger. And so the way this process works has been badly misunderstood in the kind of online literature of weight training and bodybuilding and even in sports physiology. The Heneman -sized principle is kind of a foundational principle within muscle physiology. But many people have come to interpret it by saying that the way to recruit high threshold motor units, the ones that are hard to get to, is to just use heavy weights. And that's actually not the case. As we'll talk about, the research supports that weights in a very large range of sort of percentage of your maximum anywhere from 30 to 80%.

9:00So weights that are not very light but are moderately light to heavy can cause changes in the connections between nerve and muscle that lead to muscle strength and muscle hypertrophy. Put differently, heavy weights can help build muscle and strength but they are not required. What one has to do is adhere to a certain number of parameters, just a couple of key variables that I'll spell out for you. And if you do that, you can greatly increase muscle hypertrophy, muscle size, and or muscle strength if that's what you want to do. And you don't necessarily have to use heavy weights in order to do that.

9:40Now I'm sure the power lifters and the people that like to move heavy weights around will say, no, if you want to get strong, you absolutely have to live heavy weights. And that might be true if you want to get very strong. But for most people who are interested in supporting their muscular such that they offset any age related decline in strength or in increasing hypertrophy and strength to some degree, there really isn't a need to use the heaviest weights possible in order to build strength and muscle. So there are three major stimuli for changing the way that muscle works and making muscles stronger, larger, or better in some way.

10:18And those are stress, tension, and damage. Those three things don't necessarily all have to be present, but stress of some kind has to exist. So this is very reminiscent of neuroplasticity in the brain. There is a good predictor of how well or how efficient you will be in building the strength and or if you like the size of a given muscle. And it has everything to do with those upper motor neurons that are involved in deliberate control of muscle. You can actually do this test right now. You can just kind of march across your body mentally and see whether or not you can independently contract any or all of your muscles.

10:58Because everything about muscle hypertrophy, about stimulating muscle growth, is about generating isolated contractions, about challenging specific muscles in a very unnatural way. Whereas with strength, it's about using musculature as a system, moving weights, moving resistance, moving the body. The specific goal of hypertrophy is to isolate specific nerve to muscle pathways so that you stimulate the chemical and signaling transduction events in muscles so that those muscles respond by getting larger. So there's a critical distinction in terms of getting stronger versus trying to get muscles to be larger hypertrophy per se.

11:44And it has to do with how much you isolate those muscles. So you can nest this as a principle for yourself, which is if you want to get stronger, it's really about moving progressively greater loads or increasing the amount of weight that you move. Whereas if you're specifically interested in generating hypertrophy, it's all about trying to generate those really hard, almost painful, localized contractions of muscle. If ever there was an area of practical science that was very confused, very controversial, and almost combative at times, it would be this issue of how best to train. I suppose the only thing that's even more barbed wire of a conversation than that is how best to eat for health.

12:27Those seem to be the two most common areas of online battle. What's very clear now from all the literature is that once you know roughly your one repetition maximum, the maximum amount of weight that you can perform and exercise with for one repetition in good form, full range of motion. That it's very clear that moving weights or using bands or using body weight, for instance, in the 30 to 80 % of one rep maximum, that is going to be the most beneficial range in terms of muscle hypertrophy and strength. So muscle growth and strength. So let's say you're somebody who's been doing some resistance exercise kind of on and off over the years, and you decide you want to get serious about that for sake of sport or offsetting age range.

13:20So that's what's very clear now. The range of sets to do in order to improve strength ranges anywhere from two, believe it or not, to 20 per week. Again, these are sets per week and they don't necessarily all have to be performed in the same weight training session. It appears that five sets per week in this 30 % to 80 % of the one repetition maximum range is what's required just to maintain your muscle. So think about that. If you're somebody who's kind of averse to resistance training, you are going to lose muscle size and strength. Your metabolism will drop, your posture will get worse. Everything in the context of nerve to muscle connectivity will get worse over time unless you are generating five sets or more of this 30 % to 80 % of your one repetition maximum per week.

14:10Okay. So what this means is for the typical person who hasn't done a lot of weight training, you need to do at least five sets per muscle group. Now, that's just to maintain and then there's this huge range that goes all the way up to 15 and in some case 20 sets per week. Now, how many sets you perform is going to depend on the intensity of the work that you perform. This is where it gets a little bit controversial, but I think nowadays most people agree that 10 % of the sets of a given workout or 10 % of workouts overall should be of the high intensity. So the sort where one is actually working to muscular failure.

14:50But the point being that most of your training, most of your sets should be not to failure. And the reason for that is it allows you to do more volume of work. So we can make this simple, perform anywhere from five to 15 sets of resistance exercise per week. And that's per muscle and that's in this 30 to 80 % of what your one repetition maximum. That seems to be the most scientifically supported way of offsetting any decline in muscle strength if you're working in the kind of five set range. And in increasing muscle strength when you start to get up into the 10 and 15 set range. But it's pretty clear that performing this five to 15 sets per week, whether or not it's in one workout or whether it's divided up across multiple workouts is really what's going to be most beneficial.

15:42And please do keep in mind, Hennamann's size principle and the recruitment of motor units. And remember the better you are at contracting particular muscles in isolating those muscles, the fewer sets likely you need to do in order to get the desired effect. As many of you know, I've been taking AG1 daily for more than 13 years. However, I've now found an even better vitamin mineral probiotic drink. That new and better drink is the new and improved AG1, which just launched this month. This next gen formula from AG1 is a more advanced clinically backed version of the product that I've been taking daily for years.

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16:47I discovered and started taking AG1 way back in 2012, long before I ever had a podcast and I've been taking it every day since. I find that it greatly improves all aspects of my health. With each passing year, and by the way, I'm turning 50 this September, I continue to feel better and better, and I attribute a lot of that to AG1. AG1 uses the highest quality ingredients in the right combinations, and they're constantly improving their formulas without increasing the cost. So I'm honored to have them as a sponsor of this podcast. If you'd like to try AG1, you can go to drinkag1 .com slash Huberman to claim a special offer.

17:22Right now, AG1 is giving away an AG1 welcome kit with five free travel packs and a free bottle of vitamin D3 K2. Again, go to drinkag1 .com slash Huberman to claim the special welcome kit with five free travel packs and a free bottle of vitamin D3 K2. What about people who have been training for a while? If you're somebody who's been doing weight training for a while, the data point to the fact that more volume can be beneficial, even for muscles that you are very efficient at contracting. Now, the curve on this, the graph on this begins again at about five sets per week for maintaining a given muscle group and extends all the way out to 25 or 30 sets per week.

18:03However, there are individuals who, for whatever reason, can generate so much force, they're so good at training muscles that they can generate so much force in just four or six or eight sets that doing this large volume of work is actually going to be counterproductive. So everyone needs to figure out for themselves. First of all, how often you're willing to do resistance exercise of any kind. And then it does appear that somewhere between five and 15 sets per week is going to be what's the thing that's going to work for most people. Now, this is based on a tremendous amount of work that was done by Andy Galpin and colleagues Brad Shonefield and colleagues Mike Roberts.

18:42There's a huge group of people out there doing exercise physiology and a small subset of them that are linking them back to real world protocols that don't just pertain to athletes. So that's mainly what I'm focusing on today. And surely there will be exceptions. Now, if you are going to divide the sets across the week, you're not going to do all 10 sets, for instance, for a given muscle group in one session, then of course, it's imperative that the muscles recover in between sessions. You might ask, well, what about the speeds of movements? This is actually turns out to be a really interesting data set for generating explosiveness and speed.

19:19It's very clear that learning to generate forces quickly and to move heavy or moderately heavy loads quickly is going to be beneficial because of the way that you train the motor neurons and of course changes in the muscle. And so what this would involve is something like 60 to 75 % of a one repetition maximum. And then in a controlled way, moving that as quickly as one can throughout the entire set. And certainly not going to failure because as you approach failure, the inability to move the weight with good form, the weight inevitably slows down. So as you're probably starting to realize, you need to customize a resistance practice for your particular needs and goals.

19:59So we've talked about a few principles, the fact that you need to get sufficient volume. You need at least five sets to maintain and you probably need about 10 sets per muscle group in order to improve muscle that moving weights of moderate to moderately heavy weight quickly is going to be best for explosiveness that isolating muscles and really contracting muscles hard, something that you can test by just when you're outside the training session, seeing whether or not you can cramp the muscle hard will really will tell you your capacity to improve hypertrophy or to engage strength changes in that muscle.

20:30That your ability to contract a muscle hard is inversely related to the number of sets that you should do in order to isolate and stimulate that muscle. Now how long to recover between sets? There's a question for the testosterone protocol, Duncan French and colleagues found that it was about two minutes keeping that really on the clock, two minutes, not longer for hypertrophy and for strength gains. It does seem that resting anywhere from two minutes or even three or four or even five or six minutes can be beneficial. So how do we know if we've recovered? How can we test recovery? And this is not just recovery from resistance training.

21:05This is recovery from running recovery from swimming up until now I've been talking about resistance training more or less in a vacuum. I haven't even touched on the fact that many people are running and they're doing resistance training or they're swimming and they're doing resistance training. Well, you can assess systemic recovery, meaning your nervous system and your nervous system's ability to generate force, both distributed and isolated through three main tests. And fortunately, these tests are very simple and two of them are essentially zero cost required no equipment. HRV heart rate variability has made its way finally into the forefront of exercise physiology and even into the popular discussion.

21:50I've talked about HRV before how when we exhale our heart rate slows down because of the way that our diaphragm is connected to our heart and to our brain and the way our brain is connected to our heart. When we inhale our heart rate speeds up and that is the basis of heart rate variability heart rate variability is good, but heart rate variability is difficult for a lot of people to measure. There are two measures however, whether or not you recovered that you can use first thing in the morning when you wake up in order to assess how well recovered you are and therefore whether or not you should train your whole system at all that day.

22:22The first one is grip strength. Grip strength, the ability to generate force at the level of squeezing the fist or squeezing down on something might seem like kind of a trivial way to assess recovery, but it's not because it relates to your ability to use your upper motor neurons to control your lower motor neurons and to generate isolated force. That's really what you're assessing when you do that. Some people will use one of these grip tools. If I've been working really hard not sleeping very well or I've been training a lot, any one or combination of those things, my grip suffers. I can't actually squeeze that thing down as much as I can, but on a good day I can squeeze this thing so that I eliminate the hole in the doughnut so to speak.

23:04You can also take a floor scale and squeeze the scale and see how much force you can generate. I would do that as a baseline to establish what you can do when you're well rested. And then if you do that in the morning you can see whether or not you're able to generate the same amount of force. A lot of this is very subjective with the scale. You're really trying to assess whether or not you can generate the same amount of force. If you start seeing a 10 % or 20 % certainly reduction in that, that's concerning. It means that your system, that your nervous system as a whole, it's not necessarily fatigued, it's that the pathways from nerve to muscle are still in the process of rewiring themselves in order to generate force.

23:42And you might think, well, I trained one muscle group one day. Why am I having a hard time doing this for a completely different muscle group? Doesn't make any sense. But there's something about the upper motor neuron to lower motor neuron pathway generally that allows you to use something like grip strength as it kind of a thermometer, if you will, of your ability to recover. So look for your ability to generate force in grip when you first wake up. It's not going to be as good as it is at the 3pm after a cup of coffee and a couple meals. But that the point isn't performance overall. The point is to assess whether or not you're getting better, worse or the same from day to day.

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