Chapters:
00:00 Intro
00:58 Mind-muscle connection is not a science-based concept
01:16 Intentional focus and EMG research
03:20 Mind-muscle connection when training explosively
04:00 Why can’t we activate the muscle more by focusing on it?
09:11 What about muscle growth?
13:06 Conclusion
14:53 Outro
Transcript:
When you’re in the gym, should you focus on movements or muscles? The general thinking is that for bodybuilding you want to use the mind-muscle connection, whereas for powerlifting you focus on performance and technique. Using the mind-muscle connection in this context means that you focus on the target musculature that you’re trying to grow to activate it more and get a better growth stimulus. So when you’re squatting and you want a bigger booty, you focus on the glutes. When you’re bench pressing, you want bigger pecs, you focus on that sweet squeeze of the pecs. Indeed, we have direct research showing that if we focus on a muscle group when we exercise, that muscle group can activate more. We also have studies that, in the long run, focusing on a muscle group in a training program can make it grow more. So, case closed, right? Not so fast.
In this video, I’m going to make the case that these studies have significant limitations and they obscure the bigger picture. I’m going to tell you how to lift from maximum growth and maximum strength development and it’s not by using the mind-muscle connection.
Some skepticism towards the mind-muscle connection is warranted simply because it’s not a scientific concept. The concept was basically unheard of in exercise science literature until 2012. Instead, the term comes from bodybuilding circles. Now, that doesn’t mean it’s bro science, but a little skepticism is warranted. So let’s look at the actual studies. Multiple studies have looked at the effect of attentional focus on EMG muscle activity. Electromyography measures muscle activity. It suppose to measure the electrical, or the neural impulse that your brain sends to the muscle to activate it. While it has significant limitations, the EMG research is quite clear that we can, in fact, activate a muscle more by focusing on it. Most of these studies have focused on the bench press and what they do, for example, they have people perform a couple repetitions by focusing on either the triceps, the pecs, or just focusing on performance. What you see in these studies is that when you focus on the pecs, the pecs activate more, when you focus on the triceps, the triceps activate more, exactly as you would expect based on the mind-muscle connection. However, here’s the catch: all of these findings are with low exercise intensities, training very far away from failure, typically doing just a few repetitions with intensities as low as 20% of your 1RM. Even at 50 to 60% off 1RM we see that mind-muscle connection becomes very unclear in its effects and there is often no significant effect anymore. At 80% of 1RM, and only doing a few repetitions, so nothing like a real work set, we see that the effect is almost entirely gone.
In addition to the studies on the bench press, one study illustrates this well for rows. One group was instructed to just perform the exercise without any explicit instructions and the other group was instructed to pull from the back. Now you could see that when they perform the set, at the start there was indeed increase in lat activity, but there was a decrease in posterior deltoid activity. So it’s even questionable if we can use the mind-muscle connection, if that’s advantageous, because the muscle activity might come at the expense of another muscle group. Still, what happened is that after the first 2 to 3 repetitions the effect disappeared. Interestingly, the negative effect on the posterior deltoid lingered a little bit longer than the positive effect on the lats and throughout the set as a whole, on average, there were no significant differences anymore between the groups in muscle activity levels. And this was not even to true failure, this was a set at 70% of 1RM, until they lost movement velocity. So that’s still quite far from failure. Now, the researchers concluded: “Verbal instruction seems to have little effect on the increasing myoelectric activity of these targeted muscles in an entire set of resistance training.”
The effect of the mind-muscle connection also disappears when we train more explosively. When researchers compared lifting explosively and trying to focus on their pecs or triceps in a bench press, versus not explosively, they found that only when you were lifting not explosively and with a low intensity and far away from failure, then you could increase triceps activity by focusing on the triceps and pec activity by focusing on the pecs, but if you are lifting either heavy weights, or you’re getting closer to failure, or you’re lifting more explosively, then you don’t get the effect anymore. So basically, anything that approximates reasonable levels of muscle activity that you would get in heavy training negates any of the effects that we still see of focusing on a muscle group to increase its activity even further.
So why can’t we activate the muscle more by focusing on if we’re training hard in any way? Well, one explanation: You might argue that these participants were just not trained enough. A common complaint from people that have no understanding of scientific research is that research is some weird, magical thing that happens in a laboratory with people that don’t even lift, and they’re doing all of these crazy, completely theoretical protocols that have no bearing on how the real people lift. In reality, that is not the case. Many exercise scientists lift themselves and many of the trainees in studies lift harder, I would say, than the average gym goer, because they get instructed to train as hard as they can and when people train with someone shouting in their ear, they train a lot harder. In this particular case we also have direct studies that compared the effect of the mind-muscle connection in trained and in untrained individuals and they consistently found no significant differences between the groups. So training experience itself does not seem to make us better at using the mind-muscle connection.
This is one of those cases where we like to think, as trainees, that we get better just from doing. But we don’t get better at something by doing it, we get better by doing something and getting feedback on what we did wrong or what we did right. In the case of the mind-muscle connection we don’t have that feedback. Sure, you feel something, but there’s no bearing that that something is actually muscle activity or mechanical tension, so, basically, you’re just focusing on the muscle and that in itself doesn’t make you better at it. You don’t get the feedback whether you’re actually increasing the muscle activity, whether there’s actually more force production, whether the muscle is actually producing more tension.
Now, the real reason that the mind-muscle connection doesn’t work to increase muscle activity is because our brains are too awesome. The motor cortex, which is the part of your brain that governs movement, has been fine tuned by millions of years of evolution to perform its tasks exceedingly well. And it functions as a Bayesian system. It’s very efficient and if you tell it what to do, like -you have to throw a ball, this goes there- then it will do that exceptionally well. And with our conscious thought we like to think, as bodybuilders we know how the human body works so we can manipulate it very easily. Like, we know the biceps is an elbow flexor, we know the triceps is an elbow extensor, So we like to think, okay, so we can manipulate the body. Well, try thinking of a movement that’s a little bit more complex, like running. Which muscles exactly do you activate while running? Which muscles do you feel? It suddenly becomes very complex.
Indeed, movements like running, walking or throwing an object are so complex that even the brightest mathematicians have been unable create robots up until around now, that do anything like walking with any sense of grace. So, in a sense, trying to improve on our motor cortex because we have a rudimentary understanding of functional anatomy is a lot like trying to poke into your motherboard with a kitchen knife to make your computer run faster. What happens with the mind-muscle connection, which is a form of internal cueing- you focus on something inside the body, the motor cortex faces what’s called constrained optimization. Normally when you instruct the body what to do, it will do it exceedingly well and at a subconscious level, it will optimize exactly what the activity of every muscle group is, how much we activate the biceps, how much co-activation is there from the triceps, when exactly do we start activating the triceps, when do we start engaging the hips…
All of these things, they occur subconsciously with a high degree of precision and when we constrain this process by saying: “Okay, now we want to lift the weight, but we have to do it with our pecs.” what we see in research is that this reduces the efficiency of the movement a lot, because naturally, our brain would select the optimal solution for this movement pattern, and when we constrain it in a way, that solution becomes less optimal, so less efficient. And that’s why we see in research that when you do this with low weights or when you’re not lifting explosively, the movement gets harder because it’s less efficient and therefore we see that muscle activity levels go up. It’s like trying to deadlift your 1RM by focusing on only lifting with the quads. You cannot even lift the weight. So when you’re lifting a lighter weight, essentially, when you’re doing it with your quads, it’s like you’re lifting a higher percentage of your 1RM. Because your 1RM is lower when you use an internal cue, like focusing on a muscle, than when you use an external cue, something outside the body, like making sure the weight goes up. If you think about it, this knowledge is very intuitive. If you want to throw a dumbbell at someone doing curls in a squat rack, you don’t think: “When do I activate my triceps?” You just think: “This goes to his head.” By the way, don’t actually throw dumbbells at people curling in a squat rack. It’s almost as impolite as curling in a squat rack to begin with.
We have lots of research that internal cues reduce performance and, very importantly, also reduce long term strength development. So when you use external cues, like technique, lifting as much as possible, you get better performance during sets, you can typically perform more repetitions with a given weight and you get better long term strength development. For example, one study found that doing a ten rep max with squats and deadlifts, people can generally do 1 to 2 repetitions extra when they focus on lifting as much weight as possible versus when they focus on using their legs. So to recap, muscle activity does not increase when you use an internal cue, force production does decrease when you use an internal cue, and you also see this in the studies, by the way, that ground reaction forces are lower in the studies, for example, when we look at squats and deadlifts when people focus on using their legs versus when people focus on lifting as much weight as possible. So there’s actually more total force production which is why your performance is higher when you are focusing on your performance than when you’re focusing on your muscles.
So we see no increase in force production, logically then also no increase in mechanical tension in the muscle because there’s no increase in muscle activity or force production, we see worse strength development when people use internal cues or at best equal strength development in some studies, but what about muscle growth? Because you might be saying: “Look, I don’t care about any of these things, Menno, I just want to get jacked.” I understand.
Unfortunately, we have only one study that directly looked at the effect of attentional focus on long term muscle growth. This study had two groups of individuals perform barbell curls for the biceps and leg extensions for the quads during a 10 week training program. One group was simply instructed to get the weight up and the other group was instructed to squeeze the muscle. At the end of the program the leg extension group did not gain any more muscle. Muscle growth was the same regardless of whether the individuals focused on squeezing the muscle or getting the weight up. For barbell curls, however, biceps gains, muscle growth in the biceps, was greater in the group focusing on squeezing the biceps than the group focusing on just getting the weight up. Why did it work for one muscle group and not the other muscle group? Well, the researchers speculated that the individuals couldn’t establish a good mind-muscle connection with their quads, whatever that means. To me, this doesn’t sound like a very scientific explanation, especially not considering the earlier research that we have on the mind-muscle connections. General failure when training to failure.
It’s also worth noting that body composition, skeletal muscle mass and isometric strength gains, which normally correlates very well with muscle growth, did not actually differ between groups, suggesting that the greater biceps growth might have been a type I error or a false positive. However, let’s say that the results are accurate, we take them at face value there was greater biceps growth, which is probably the case, why is it that it works for the biceps but not for the quads? I think when you instruct people to just get the weight up during barbell curls, what usually happens is that people go full Arnold Schwarzenegger and they go like: “Aaaaaaarrrrgggghhhhh!!!!!!” they do, like, more like a reverse power clean, where the elbows come way forward there’s some hip movement and it’s not a clean biceps curl. The leg extension is nicely restrained in its movement, so you can try to just get the weight up however you want, but you’re in a fixed machine so the leg only goes one way. It doesn’t matter what you focus on, the movement is exactly the same. Given the exact same movement, you get the exact same outcomes from movement. So I think the greater gains in the biceps curl group were the result not of focusing on the biceps, but of simply having better exercise technique that therefore stimulated the biceps more.
What you typically see when people just focus on lifting the weights at all costs with the biceps curls is that range of motion gets compromised. A lot of movement starts coming from the shoulder instead of the elbow, like this movement, and some from the hips as well, the eccentric phase gets less emphasis, it becomes more of a free fall. These factors could explain why we see greater muscle growth when people focus on squeezing their biceps. I think you will get the same results if you focus on good exercise technique. Why does it matter then?
Well, for compound movements it matters because you’ll get better strength gains, better performance and you don’t get negative effects on other muscle groups as you would get when you focus on one specific muscle group with the mind-muscle connection, if you get any effect at all. Moreover, we have some research indicating that it’s better to focus on exactly what you want from people, when you cue people in the gym, then focusing on a muscle group. Like, some people will naturally know what to do when you say focus on your biceps. If you’re well trained, you’re watching this video, probably you know exactly what I mean what you should do. But for an untrained individual, they don’t know. Focusing on their biceps, maybe they don’t even know what the biceps does. So it’s better to just say: “Keep your elbow at your side.” or “Perform a controlled movement.” If you see them moving their elbow forward too much you say: “Keep the elbow back.” Very clear, they know exactly what to do.
The brain, the motor cortex that governs the movement, knows exactly how to do these things. When you tell it what external movement to aim for it’s very good at doing that. Internal cues can be misinterpreted a lot more easily. We have some direct research showing that when people are squatting or deadlifting it’s better to tell them not to round their back, if that’s what you want from them, then to say: “Focus on lifting with your legs.” So what does this all mean in practice? Well, we know that the primary stimulus for muscle growth is mechanical tension on the muscle. You get that mechanical tension with high force output and high levels of muscle activity. We know that internal cues reduce performance, they reduce force production, they have no effect on muscle activity, at least not if you’re training anywhere close to failure, as you should and they reduce strength development in the long run. They probably don’t affect muscle growth, especially given these other factors. If anything, if we get higher levels of muscle activity due to the strength gains, cause strength development can increase muscle activity levels, can make your brain better at coordinating your muscle tissue and activating it more, and maybe also get higher levels of mechanical tension. So if anything, there’s also an argument to be made that these factors could improve long term muscle growth from external cues, focusing on performance and good exercise technique. Especially during compound movements I don’t recommend focusing on one muscle group because any increase in muscle activity would probably come at the expense of another, and we know that the total volume goes down, your total performance goes down.
During isolation movements If you like focusing on a muscle group, you don’t care about strength development then you can use internal cues, it’s perfectly fine. I think it’s often better to focus on exercise technique and more direct cues of what you want from the movement, but if you’re purely interested in bodybuilding purposes, it’s perfectly fine if you just like feeling your biceps when you’re doing biceps curls. And if it helps you have good exercise technique, it’s perfectly fine, but in itself, it’s not likely to improve muscle growth beyond having good exercise technique.
I’ll also say that there is a scenario in which I like to use internal cues with my students and my clients, and that’s when people are injured. When you’re injured it’s actually a plus if you’re lifting less weight, as you would get with internal cues. So when you’re injured and you have to do rehabilitation type exercises, or if you are very concerned with injury risk then internal cues can actually be a good way to get the same training stimulus for your target musculature while lifting less weight and putting less stress on your connective tissues.