What Drives Muscle Growth & What Doesn't | Dr. Mike Roberts

**Andy Galpin** (0:00)
Is it then fair to say there are a subset of people who just simply cannot grow muscle from strength training?

**Mike Roberts** (0:05)
I think the percentage of folks, when you look across different studies, the non-responders are pretty low. So that is to say that most people will see at least some growth. But I'm always devil's advocate. Yeah, okay, so they grow, but some people see a lot more growth than those people, right? So, I mean, there are clusters.
You can call it turtiles. You have low, moderate, high. Like, there is that. But that is to say that maybe less than 5% of the population, if not even smaller, that will not grow.

**Andy Galpin** (0:38)
The science and practice of enhancing human performance for sport, play, and life.
Welcome to Perform.
I'm Dr. Andy Galpin. I'm a professor and scientist and the executive director of the Human Performance Center at Parker University. Today, I'm going to be speaking with Dr. Mike Roberts. Mike has a PhD in Muscle Biology and has focused his research in his laboratory at the University of Auburn mostly on how skeletal muscle responds to strength training and resistance exercise. Mike is by far my go-to reference when I want to talk about, understand, or learn more about how and why skeletal muscle grows in response to exercise. In this episode, you're going to learn a lot about that. He will cover many practical applications such as what do we know about the style of exercise, how many repetitions, and how much volume is needed to maximize muscle growth. He'll also give you an extraordinary insight into the biology, molecular mechanisms, and cellular components that go into understanding why and how muscle grows in response to resistance exercise. With all that in mind, I hope you enjoy today's episode with Dr. Mike Roberts. Dr. Mike Roberts, it is amazing to have you here, man. I really appreciate you flying halfway across the world to coming out for a day. It's been a long time.

**Mike Roberts** (1:54)
It has.

**Andy Galpin** (1:54)
If you've ever seen any of my videos or conversations on muscle physiology, there's a strong chance it's Mike's work that I'm talking about. So I just had to have you in. We're going to spend as much time as we can today on muscle. I'm really excited because your lab has done such tremendous work in this area, covering everything from responders versus non-responders to exercise. So why are some people growing muscle and other people having a really hard time?
You guys have done a lot of work in aging. So how does this process change with age, with sex, with different nutraceuticals, and nutrition, and supplementation? But mostly, you guys have focused in on what I'll just call the molecular side. The equation, what's happening in the cell.
So with that in mind, actually, I don't think I could think of another person in our field who I've seen either science misrepresented, misquoted more than yours.

**Mike Roberts** (2:50)
Oh, wow. Thanks.

**Andy Galpin** (2:54)
People love to use your stuff as fodder for whether it's a training recommendation or something else. So I would really love for you to maybe set the table clearly on what some of your work does, what it suggests, what it doesn't suggest, sure, and otherwise. So that's the playbook, in large part. And I think it would be best for us to actually start with a broad understanding of how does muscle grow. When we say that, and we say this word hypertrophy, one of our muscles presumably our biceps, because that's what everyone cares about, right?
When it got bigger, how? Why? And then that, of course, will lead us into, if you wouldn't mind giving us an overview of what we'll call the molecular mechanisms of how that muscle grew, why it grew, and then that will give us the table to get into all the nuances of how do we optimize that, how do we alter it and change. So I'll set you up that way and I'll let you lead from there.

**Mike Roberts** (3:48)
Okay, sounds good. So how does muscle grow?
The simple answer is mechanical overload. You will see that in the literature time and time again, which is to say that weight training for humans or very, very intricate models in rodents will allow the muscle to grow. So when we say mechanical overload, if any of your viewers read that, we're referring to resistance training in the human. Consistent resistance training, and we'll get into programming. Not my forte, like we talked about everybody, Brad Schoenfeld, who is very well versed in that, but I have some ideas in terms of how to maximize hypertrophy, sets per week, that sort of thing.