Dr. Layne Norton: So let's talk about building muscle first, because it'll help frame it better. What seems to be important for building muscle is a few things. The first is mechanical tension and understanding that mechanical tension is cumulative throughout reps and sets. So when I say mechanical tension, I think a lot of people misinterpret that as it's got to be heavy, you know? And I'm like, well, if you want max mechanical tension, just do the most eccentrically loaded exercise you can possibly do. That'll be the most mechanical tension for one rep. But it's really about what is the number of hard sets that you do. And by hard sets, I mean proximity to failure.

Now, the research seems to suggest for muscular hypertrophy, you have to get within a few reps of failure to really maximize the response, but you probably don't need to go all the way to failure. And this is probably conflated by the fact that if you're always training to failure, especially compounds, your performance and the load you can use is going to drastically fall off. For example, if I did a 10-rep max set of squats, like my absolute best, I actually remember the set. I did 530 for 10 reps, I think something like that in squat. After it was done, I had to lay down for 15 minutes and I couldn't move, like physically could not move. If you ask me to do that again, I might have gotten, I don't know, 2 reps, something like that.

And so if you're, if you're doing that big compound movements like that, it's gonna be hard for you to actually get a lot of effective sets in because it's so fatiguing. Now isolation stuff, a little bit different. Single joint movements, a little bit different. You can kind of push those a little bit harder and actually probably should push those a little bit harder. One of the best descriptions I heard was intensity is the medicine. So hard sets close to failure is the medicine. The number of hard sets, or the volume we'll call it, is the dosage. So we have several meta-analyses now and meta-regressions kind of suggesting that there's kind of a dose response between number of hard sets you do and muscular growth. I mean, we've even seen it like specifically in the triceps.

There was a regression by James Krieger that even up to like 27 to 45 hard sets per week on triceps produce more muscle growth than I think like 15 to 25 sets per week, something like that. So now again, I want to couch that with you're going to get most of the benefit if I am always looking at things like, how can I be the most muscular, strongest human being I can? But for the average person, if you just want to grow some muscle, you don't have to do that many sets. But the point is, it does seem to be kind of a dose response.

Dr. Rhonda Patrick: For someone who may not know what failure is, how do you identify close to failure?

Dr. Layne Norton: That's actually where practically I think most people probably should train to failure at a certain point, because otherwise it's really hard to determine what failure is. And actually, there are studies on this, and on average, intermediate and beginner lifters underestimate their, uh, their repetitions they can achieve by about 5 to 6. So for example, in a study, they might have them say, like, intra-set Say on their 8th rep, how many do you think you have left? 2. Okay, then the next set they actually— they yell at them, they blare music, they're like hyping them up, and they'll get 15 or 16 reps, right? And so I think a lot of people, if they've never trained to failure, they viewed failure as kind of like discomfort.

And in fact, it's funny because I've had people say, well, you— and I'm going to get into this about the strength stuff— I almost never train to failure, especially on compounds. And say, well, you— I've had people say, you train like a wuss, you know, you stop, you know. I'm like, so, okay, so that set of 10 with 530 that took me out, but honestly took me out for weeks after that, to be honest. You're saying if I stop 2 reps short of the 10th rep that that was an easy set. I can tell you every single rep of that set was hard and felt uncomfortable. Okay, and so I think people, if they've never trained to failure, it probably is a useful experience to do with a spotter under conditions like— be smart, right? But I do think it is useful.

Now When it comes to bodybuilding and growing muscle, whether you train to failure or stop shy, similar effects. But you probably want to stop on compounds. And again, I'm guessing based on some of these meta-regressions. I could come out, I could be a little bit off, but I think I'll be pretty darn close. On compound lifts, big compound lifts, probably need to get within 2 to 3 reps of failure to get the maximum benefits. For isolation, probably 1 or 2. But for powerlifting, this is where it gets quite different. And again, there are bodybuilders who train to failure on every set and are very strong. There are powerlifters who are very strong who don't look super muscular.

And so people will— there's actually like some people in the scientific community who will say like things like muscle mass doesn't matter for strength. I think very strongly that they're incorrect. And there are people who will say, well, strength doesn't matter for hypertrophy. I think strongly that you're also probably incorrect, okay? Because all things being equal, let's take somebody who wants to grow muscle. All things being equal, if they are stronger, they can create more mechanical tension. They can do the same reps with more weight, okay? That's a bigger potential. Take somebody who's a powerlifter. All things being equal, if they have more muscle mass, they will be stronger.

And one of the things I tell people is, well, if muscle mass doesn't matter for powerlifting, then I'm just gonna lose 40 pounds, drop down to whatever weight class I need to hit world records. No, it matters. Mass moves mass. But I think people, for example, me, I held a world record squat for almost a year, hit 668 pounds in 2015 at IPF Worlds.

Dr. Rhonda Patrick: Wow.

Dr. Layne Norton: And I don't— I've got good legs by most people's standards, but if you put me on a bodybuilding stage, I'll never have the best sets of legs on stage. And they'll see somebody who has really great legs who only squats 500 pounds, and the, the, the conclusion will be, okay, well, muscle mass doesn't matter for strength.

No, because that person For them, because I don't know what their motor neuron recruitment is like, I don't know all that kind of stuff. But all things being equal, if they have less muscle, they'd be weaker. If they had more muscle, they'd be stronger, right? So same thing for me. Now, when it comes to strength, the purest expression of strength is force, right? You have to produce force, and that's mass times acceleration— actually, mass times acceleration squared, right? I think. Physics people, please check me on that one. But there's a mass component and there's a speed component to it. So you can move a given load with the same force as you move a heavy load, you'll just move it faster, right?

So now if it's a heavy load, you can apply the same force, but it's gonna move slower, right? So then we call this the strength velocity curve. So one of the things that my coach, Zac Robinson, really kind of pioneer talking about, and he came out of Mike Zourdos's lab at FAU, was he said, you know, a lot of powerlifters or people who are trying to build strength train with a lot of fatigue. You know, they're training very close to failure. You know, they're doing heavy sets. And that is one thing that's very important for strength. If you want to get better at a 1-rep max, you have to be doing sets with, you know, heavy singles, doubles, triples, because that is a specific skill set.

You need that to, one, learn how to grind hard reps, and two, just feel what heavy weight feels like and how to manage that under stress. So you need those sets, but then volume is also important for strength. There's quite a few studies that show that. But interestingly, he did a, I believe he did a meta-regression looking at hypertrophy, showing that proximity to failure kind of was linearly associated with more hypertrophy. So the closer you got to failure, the more hypertrophy you got. The strength regression didn't show that. It had no association with your proximity to failure. And so one of the things they said is with strength, you're always managing kind of expression with fatigue.

So if you're training heavy a lot and going close to failure, you're doing a very specific skill, but you're also inducing a lot of fatigue, which is going to reduce the amount of strength that you can express. Whereas the way we kind of train, or he trains me, is we'll— when I'm doing my compound squat, bench press, deadlift, I'll do 1 set or maybe 2 sets of a heavy single, double, triple, maybe 4 reps. And then we'll do back-offs that are much lighter, but we're doing multiple sets of them as fast as we can, like the speed of the rep as fast as we can. And they've actually shown that you get better strength results not training to failure compared to training to failure. But you do have to do some heavy, heavy sets relatively close to failure.

And it's probably because, like I said, failure just induces a lot of fatigue, and that's going to mask how much strength you can actually express when they test it. So in general, this is kind of minutiae that a lot of people don't really need to worry about. I always tell people, you know, I'm 90% sure that you're not training too hard. I'm almost sure of that. Okay, there are people who do train too hard. There are people who overtrain themselves. There are people who put in so much fatigue that it's going to mask their results. But for the most part, most people All the— there's so many people I see online who think they're overtraining, and I'll look at their training and I'll be like, no, no, you're not overtraining. And if you are, you're not sleeping well, or your nutrition's crap, or something like that.