Ep. #256: Research Review: Greg Nuckols on the “Mind Muscle Connection” and Muscle Building

Mike: Hey, Mike here back with another episode of the muscle for life podcast. And this time I am speaking with the one and only Greg knuckles who is a world record holding power lifter, researcher and coach and one of the four most authorities on the science of strength training. His website www.

strongerbyscience. com is one of the best resources for the hardcore science of weightlifting. It’s not particularly for laymen, but if you really like to geek out on all of the technical stuff, you will really like Greg’s work. And Greg also produces a fantastic monthly research review along with Dr.

Eric Helms and Dr. Mike Zortos. Both of whom have been on my show to talk about the science of making gains. And that research review is called mass M a S S. And you can learn about that at stronger by science. com slash mass M a S S. Now in this interview. Greg is going to break down one of the studies analyzed in that review, and this study looked at what many people call the mind muscle connection.

And this study looked at how it relates to muscle and strength gain, and Greg He’s going to break it down. He’s going to explain what the mind muscle connection is, what this particular study had to say about it and how that squares with the rest of the literature. How you might incorporate the mind muscle connection in your training and what to expect from it as well as what not to expect from it and more.

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That is enough shameless plugging for now. At least let’s get to the show. Greg, welcome back. The last time you were on, we were talking about strength, the correlation between strength and size. That one was really popular. People really like that. It still gets a lot of listens now today. I keep an eye on it because it just keeps going.

Sweet. Glad people like it. Very cool. Yeah. So this is going to be a research review. I’m excited to have you on. I’ve had Eric on. I’ve had Mike on. So now complete the the Troika, the trifecta. What are we talking about today? Are we talking about mind muscle connection and how cueing Relates to that.

And I’m going to just allow you to start and explain to everybody listening. What is the mind muscle connection or what is it purported to be? What is queuing? And then let’s get into the study that you reviewed in your monthly research review. And what can we learn from it? 

Greg: Yeah, absolutely.

Mind muscle connection is basically the idea. That when you’re performing an exercise, if you specifically focus on trying to use whatever muscle you’re trying to build with that exercise that you’ll be able to use that muscle more activated more. And hopefully, theoretically, that will lead to more muscle growth.

In the research, generally, mind muscle connection type stuff is researched via cueing. There’s two broad categories of cues. Those are internal and external cues. And internal cues are more like mind muscle connection type cues. So if someone is performing the bench press, you tell them like, squeeze your pecs, something like that.

Whereas external cues are less focused on your muscles or what parts of your body you’re doing and more focused on the outcome of the movement itself. So also for bench press, you could say drive yourself into the bench or try to throw the bar through the ceiling, something like that. in most of the research to this point.

They find that internal cues across like a broad variety of exercises, including things outside of the gym. So even stuff like throwing darts, tossing beanbags, internal cues tend to increase muscle activation as assessed by EMG EMG stands for electromyography, essentially, you just have sensors attached to the skin over the muscle that pick up on the electrical activity in the muscle.

Okay. And for muscle fibers to be activated, they’re stimulated by a motor nerve, and you can pick that up as an electrical signal. So that’s what they’re doing there. So internal cues tend to increase muscle activation. But they tend to decrease performance, at least relative to external queues or no queues that could be decreasing accuracy for some sort of like accuracy task, or it could mean decreased weight lifted or moving weight at a slower speed.

For example, external queues, on the other hand, they tend to increase performance again, whether that be like accuracy type stuff, or whether that be. Bar speed weight lifted, but a lot of the research up to this point has showed lower E. M. G. lower muscle activation when compared to internal cues. The problem with a fair amount of the research up to this point.

is when they’re comparing internal and external cues. So cues focused on performance versus more like mind muscle connection. Fair amount of the studies have either used like isometric or isokinetic exercises, which essentially involve big fancy machines where Either you’re just pushing against immovable objects, that would be isometric or isokinetic.

The speed of the exercise is fixed. So for knee extension, it could be fixed at 60 degrees of knee extension per second or something like that, which obviously isn’t how most exercises in the gym are performed. So there will be parts of the movement where you can move the weight faster, parts where you can move the weight slower, just based on your natural strength curve.

Yeah, the exercises in the study protocols have been contrived in a fair amount of that research up to this point. The study I reviewed in mass, I thought was really neat and really applicable because it examined these two different types of cues in more of a real world setting.

So the title of the study was influence of different intentional focus on EMG amplitude and contraction duration during the bench press at different speeds. So essentially what they did in this study is they had people bench press 50 percent one rep max with six different conditions. So for three of them, they were intentionally lifting with a controlled rep cadence.

I think it was like Two second rep which is a pretty slow rep at 50 percent one rep max, especially. So for three of them, they lifted controlled for three of them. They lifted explosively. And then for each of those two groups of three for one of the trials, they told them just push the bar the way you typically would for one of them.

They said really focus on your pecs while you’re doing this. That would be an internal cue trying to get some peck mind muscle connection for one of them, they said, really focus on your triceps when you’re doing this. So really. Try to get like tricep mind muscle connection in the bench press six total conditions to no queuing to Peck focused queuing to tricep focused queuing.

And then for each of those sets of cues or lack of cues, one explosive trial and one controlled lifting trial. And so what they found in this study is that when the people were lifting at a slow rep cadence, the Peck focused queuing and the tricep focused queuing were effective for at increasing EMG the way they’d expect to.

When comparing PEC focused cueing to no cueing with a controlled rep cadence, PEC EMG increased, tricep EMG was unchanged. And with tricep focused cueing, interestingly, both tricep and PEC EMG increased relative to the control condition. So that’s pretty cool. And that would seem to back up a lot of the research in the area up to this point that, internal queuing, focusing on the mind muscle connection can increase muscle activation.

But then the interesting thing is the trials where they lifted explosively. And with explosive lifting, muscle activation is going to be higher regardless because you’re outputting more force. And to create more force, you need to recruit more motor units. And that is going to mean like higher EMG, higher muscle activation.

So they found that muscle activation for explosive lifting was higher than that for controlled lifting regardless of the cues given and with explosive lifting internal focus. So focusing on Peck or tricep mind muscle connection didn’t actually increase EMG anymore. So I think the two things to take away from this Is that if you are lifting slow and controlled, even with weights, you could lift much more explosively, really focusing on the mind muscle connection very well could increase muscle activation, which is pretty cool, which then theoretically would lead to more hypertrophy, although that’s still somewhat tentative, although there is I’ve heard a study coming out.

Soon from Dr. Brad Schoenfeld validating that concept, which is pretty neat. Cause that’s been a pretty big gap in the literature for a 

Mike: long time. It might be a silly question but I’m just going to ask it. What’s the practical value of that though? If you are, let’s say lifting at a high RPE where you’re going to have a lot of muscle fiber recruitment, regardless, if you’re pushing yourself, let’s say you’re lifting heavy ish weights, high RPE, do you think you would really make a difference?

Greg: Man, that’s a good question. I’ll need to wait to see that study come out to really look at the methods and see how they set things up. Because, yeah, if they weren’t pushing them to failure, then that would make sense. If you’re focusing on activating a particular muscle and still staying shy of failure, then, you’d have one group with reasonably high muscle activation the whole time.

One group with somewhat lower muscle activation that wouldn’t creep up as they approached failure. That will be like a very key component of that study. Like seeing whether they were taking them to failure or not. 

Mike: Because practically speaking, then if people listening, if it’s like you could just take 50 percent then, and you don’t, you could work in a low RPE.

You’re leaving a lot of reps in the tank, but if you really focus on the mind muscle connection, like I just see the, the PDF pushers, this is going to be the next thing. Not that’s the fault of, Brad or you or anybody else, but just people listening to understand the practicality of that, that’s the question is if you’re lifting correctly, a lot of your work is going to be done with heavier weights, higher PE, meaning you’re going to be ending probably most of your sets with one or two reps left in the tank.

And when you do that and correct me if I’m wrong here, Greg, but you’re going to be probably recruiting maximal muscle fiber. Just do that alone. 

Greg: No I very much agree with that. This may be going somewhat into the weeds, but the relationship between motor unit recruitment and hypertrophy is actually still unknown which is something that I don’t think most people are aware of.

So people assume. That you’re lifting weights, you recruit muscle fibers and that stimulates them and then they grow and everything’s nice. I think that’s the model people have in mind, but logically, there has to be some sort of fatigue component to it as well. And the reason I say that is that so when you look at research on strength training, hypertrophy of both type 1 and type 2 muscle fibers.

Which if all that mattered was just recruiting muscle fibers for them to grow, you wouldn’t expect resistance training to really do anything for type one muscle fibers, because Anytime you’re moving around throughout the day, like your lowest threshold motor units are being recruited to do that. 

Mike: And just so people listening, type one is the slow twitch.

It’s the more endurance muscle, whereas type two is the fast switch, the muscle that can generate a lot of force and generate a lot of power. And that’s the muscle that we are building when we are in the gym lifting weights, really. You’re building both. I guess then I’d say that the muscle fiber types just serve different functions primarily, then I guess.

Greg: Yeah. Yeah. So for anything you do in the gym for anything you do, period, your nervous system looks to see how much force you’re trying to produce. And then it always starts by recruiting your lowest threshold motor units, which are your smallest, weakest type one fibers. And then as you need more and more muscle mass to perform whatever activity you’re performing, it progressively recruits more motor units in an orderly fashion, such that your highest threshold type 2 strongest muscle fibers are the ones that are recruited last.

Yeah, where I was going with that is obviously, there has to be some sort of fatigue component as well, because let’s say you’re just walking around throughout the day. Your traps are always at least a little bit activated just to hold your scapula in place. But people notice when they go to the gym and they start dead lifting, doing shrugs, their traps grow.

And their type 2 fibers grow more, but their type 1 fibers do still grow from doing that. And if it was just purely a matter of the muscle being activated, It wouldn’t matter if you were just going around and day to day living versus lifting for your type one fibers. Yeah, I would have huge calves. Yeah, because they’re being used all the time.

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Greg: Going back to your question of aren’t you recruiting everything or pretty much everything if you’re taking a set close to failure in the first place, I’d say yes, but since there probably does have to be some sort of fatigue component for hypertrophy as well, I’d say no.

If you’re recruiting more muscle fibers at the very beginning of a set and keeping them active for a greater proportion of the set, theoretically, even though you would still end up recruiting those same muscle fibers at some point on your path to failure of that set, them being active for a greater proportion of the time may still end up being beneficial for hypertrophy, even if you would have recruited them.

Otherwise, But they wouldn’t have stayed recruited for quite as long. 

Mike: Sure. That makes sense. 

Greg: It’s really interesting because people are very confident. When they discuss things online about the relationship of recruiting muscle fibers versus those fibers, then growing subsequent to training, but that’s still like an entirely open question in physiology.

It’s very difficult to study. Like you could study it with isolated muscle fibers, like in a Petri dish in the lab. But in terms of being able to know exactly which motor units are being recruited in a living human being that’s pretty impossible. There are some really interesting approaches that people are taking to try to do that, which are incredibly math heavy and involve putting a lot more sensors on the muscle and then trying to decompose the EMG signal to isolate different motor units.

But yeah that’s still like a wide open question. So we can use EMG to tell you the general amount of muscle activation taking place early in a set. But yeah, the relationship between that and hypertrophy, like I said, the very first study on that is soon to be published. So it’s it’s still a pretty wide open question.

So as far as takeaways go, if you’re like tallying the evidence for internal versus external cueing. There’s very good evidence that external queuing is better for acute performance. So if you’re going for a one rep max bench press. You should be thinking, throw that bar through the ceiling.

You shouldn’t be thinking, squeeze my pants really hard. And in terms of long term training outcomes, not directly for strength training, but for some other outcomes, there is some evidence showing like long term benefits to external queuing as well. In terms of muscle growth, I would say this type of stuff provides.

evidence that internal queuing may be better for 

Mike: hypertrophy. How, what are your thoughts on like how the external cues though might be able to help you progress better just in terms of overload, adding more weight to the bar, gaining reps and what that turns into in terms of muscle growth, 

Greg: man, it’s hard to say.

So I think that. Increasing strength in a moderate rep range, like if you’re 10 rep maxes are going up, I think that’s a decent proxy for hypertrophy, but at the same time, you have to ask, like, how that is coming about. If you’re mostly getting that just from motor patterns getting better, and maybe not necessarily from hypertrophy, which very well could be happening with external cues.

Then it might end up being not quite as good of a proxy measure and also like just the relationship between strength gains and hypertrophy. There’s quite a bit of research at this point showing that you can get pretty similar hypertrophy with like higher load and lower load training. But strength gains are almost unanimously larger with higher load training there can be a disconnect there as well.

So acute performance and maybe performance increases might be a little bit lower with internal queuing, but that wouldn’t necessarily also mean that muscle growth was lower with internal. 

Mike: Yeah. Sure. For what it’s worth, I’ve always preferred external cues for the big lifts, just because, especially if I’m going heavy, I just have felt that it helps me not only lift more weight, but maintain proper form.

And I’ve written about the mind, some of this stuff, I dunno, it was like a year ago. It wasn’t necessarily as in depth as everything you’re going into now, but just a real simple explanation. And I’ve found that with accessory exercises, at least it’s a little bit easier to use internal queuing.

And so that’s what I, that’s what I’ve done personally. 

Greg: No, I agree. I think that’s a pretty smart way to go about it. Focus on performance with your big lifts and then no one cares what your one rep max bicep. 

Mike: Exactly. 

Greg: You don’t really need to be focused on performance for that. Just focus on activating the muscle.

Mike: Yeah. And you’re not even, you don’t really even care. You’re just like, I don’t know. Hopefully it goes up. It should go up over time, but really you’re just like my biceps are small. They need volume. So I just need to do some extra work for them. Great. That makes sense. Anything else that you.

Want to mention regarding this study or mind muscle or cues or anything, and any other points that you think are worth covering before we wrap up? 

Greg: One of the big findings that I didn’t quite get around to because we pursued another thread of conversation is that even though internal queuing led to a higher EMG at the controlled speed, it didn’t actually affect muscle activation at all with explosive lifting.

And the other thing was with explosive lifting. Muscle activation was higher than with controlled lifting, regardless of queuing. So PEC focused queuing with controlled lifting did increase relative to no queuing with controlled lifting, but like no queuing with explosive lifting still increased.

Led to higher peck activation than focusing on your pecks with controlled lifting. 

Mike: I would just say the explosive lifting is a bit closer to the bar speed you’d expect from the actual practical type of, again, heavier, heavy ish higher RPE. Because in that case, of course, then it probably would be even technically better to, Focus on the external cues when you’re, we’re going to be lifting explosively in any way.

So the internal queuing may not even help in that situation. Anyway. 

Greg: Yeah I’d agree with that. And that’s broadly in line with another study published like in 2009, I believe set up a similar way, but comparing instead of controlled cadence at 50 percent to explosive cadence at 50%, it was comparing 50 percent versus 80 percent one rep max.

And it found pretty similar things that internal cues did increase muscle activation when benching 50 percent loads, but the impact they had at 80 percent was much, much smaller. Basically, once you get enough weight on the bar that you are, like, actually having to push yourself regardless of what sorts of cues you’re using.

Muscle activation tends to be pretty similar between the queuing condition regardless. 

Mike: Makes sense. So yeah, so people listening, that’s an easy takeaway of external queues are probably better for increasing performance on your big lifts. And then if you want to focus on, really squeezing your bicep when you’re doing bicep curls.

Yeah, that makes sense. You’re not trying to necessarily curl up that dumbbell. So explosively as you are trying to lift 400 pounds off the floor or whatever. 

Greg: Yep, 

Mike: I I think that does it. Awesome. People that are listening that like this type of discussion, I’m just going to say, I highly recommend you check out Greg’s monthly research review, mass monthly applications in strength sport.

Did I get the acronym correct? 

Greg: Yes, sir. Most people say sports. 

Mike: Yeah. No, I remember. I remembered singular. So for some reason, my brain is weird like that. Sometimes little nonsensical details just stick forever. I don’t know. And then sometimes I can’t remember someone’s name after they meet them and they say, Hey, I’m blah.

And then two seconds later, I’m like, wait a minute. Who are you? No, but where can people find mass stronger by 

Greg: science. com slash mass. 

Mike: Great. And also I anyway, listening, I highly recommend check out Greg’s articles that he puts up on stronger by science, some of the best in depth stuff out there on mostly training.

That’s obviously your forte in terms of what you like, what you work on the most, it seems right. And yeah, fantastic stuff. I wish I knew as much as Greg knows about weightlifting, but I never will. So instead I’m just, I just read his stuff. I appreciate it, Mike. Absolutely. Yeah. So everybody listening, check out mass.

I think Greg do you have an offer going where like people get a free issue that they can check out or. 

Greg: Yeah. If you go to stronger by science. com slash mass dash issue dash one. There’s a free issue that you can download to, to check it out for pulling the trigger and joining the cool kids.

Mike: Sounds good. Thanks again for doing this, Greg. I appreciate it. Thanks, Mike. Hey there. It is Mike again. I hope you enjoyed this episode and found it interesting and helpful. And if you did and don’t mind doing me a favor and want to help me make this the most popular health and fitness podcast on the internet, then please leave a quick comment.

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Lastly, If you didn’t like something about the show, then definitely shoot me an email at mike at musclefullife. com and share your thoughts on how you think it could be better. I read everything myself and I’m always looking for constructive feedback, so please do reach out. All right, that’s it.

Thanks again for listening to this episode and I hope to hear from you soon. And lastly, this episode is brought to you by me. Seriously though, I’m not big on promoting stuff that I don’t personally use and believe in. So instead, I’m going to just quickly tell you about something of mine. Specifically, my high quality sports multivitamin, Triumph.

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triumph. com Dot legionathletics. com and pick up a bottle of triumph today. And just to show how much I appreciate my podcast peeps use the coupon code podcast to check out and you will save 10 percent on your entire order. And lastly, you should also know that I have a very simple 100 percent money back guarantee that works like this.

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