This idea that you should intentionally focus on squeezing and isolating the muscle that you’re trying to target when doing weight training exercises.

Where this idea come from?

This topic caught my attention from a recent issue of the mass research review where Greg’s knuckles reviewed a new study, on this topic. Now, historically there have been two sides to this debate now I’m on the one hand you’ve got bodybuilders who been arguing for decades that it’s really important to really focus on isolating the muscle you’re working because you’ll be able to activate it better and force it to grow as a result.

Then more recently, on the other hand, you have more academic types arguing that well the mind-muscle connection doesn’t really matter all that much because as long as you’re taking the weight through a full range of motion and the muscles are gonna have to be firing anyway in order to get the weight up. “I’m so according to them what you should instead think about is how you’re moving your body in 3d space and how you’re executing the movement properly? and you don’t need to worry too much about activating specific muscles since they’re going to be active if you move the weight regardless.”

“I’m not up to this point I think that as a whole the scientific data has been somewhat in favor of not using internal cueing or what we would call a mind-muscle connection and instead of using external cueing so just focusing on proper execution and just moving the weight.

As shown in this 15-year review of attentional focus. When it comes to things like stability, balance, endurance, and even force production in sports specific contexts. External focus beats internal focus pretty much across the board but still up until now well there has been a good deal of research measuring acute variables like EMG activation and performance.

There hasn’t been a single long-term training study looking at whether an internal or external focus would result in better muscle size and strength gains.

2018 study out of Dr. Bradshaw infield’s lab. Here, they took 27 college-aged men and randomly assigned them to either an internal focus group, so they were told to squeeze the muscle or an external focus group where they were told to focus on getting the weight up. They trained for eight weeks doing four sets of eight to twelve reps on the standing barbell curl and a leg extension only. All sets were taken to concentric failure and they use progressive overload each week adding weight when possible.

After the weeks they measured hypertrophy of the biceps and the quads and they found that there was significantly more biceps hypertrophy in the internal focus or the mind-muscle connection group but there is no difference in quad growth between the two groups.

As you can see here in the graph from the mass research review the results were pretty impressive over five percent more growth over just eight weeks by simply focusing on squeezing your biceps.

Why does the mind-muscle connection only work for the biceps and not for the quads?

The author of this paper suggests that it could be because people seem to simply have better control of and coordination with their upper extremities compared with their lower extremities. “I think this does make some intuitive sense your upper limbs are often better at performing fine motor tasks that require more precision and your lower limbs usually aren’t as good. They also bring up that perhaps this is something that could be trained over time.

They also measured strength gains in this study and they did that through asymmetric testing. So basically measuring how much force you can exert against an immovable load and it didn’t find any statistically significant differences between the groups. So at this point, on the whole, it really seems that since there isn’t any difference in strength but there is better muscle gain with the internal focus approach. This really seems like an obvious win for the bros and for the mind-muscle connection.

Study limitations

It’s important to keep in mind that we’re only looking at single joint isolation exercises in a moderate rep range here. So, I don’t think that these results should be too loosely extrapolated to other heavier compound exercises like squats, presses, and deadlifts.

In fact, based on previous research “I would expect that if compound exercises had been used the external focus group so just focusing on getting the weight up would probably have seen better strength gains than the internal focus group.”

Strength outcomes were measured using an isometric strength test which may not capture what is supposed to be the main benefit of using an external focus which is to improve motor performance.

When you think about it if you’re just pushing against some immovable object you aren’t really testing your true motor performance and its relation to strength but still, motor learning and performance is generally not a big player when it comes to these single joint movements.


We really are starting to develop a solid evidence base for the mind-muscle connection and in light of this new data “I would say the idea that the mind muscle connection leads to greater size gains is not busted.”

Our recommendations

  • Use external cuing (focus on how your body is moving in space) For heavy compound exercises like squats, deadlifts, and presses, especially when going heavy (below 8 reps)
  • Use a mind-muscle connection with isolation exercises where the goal is to target a specific muscle. For example, bicep curls, cable flyes, leg extensions, and leg curls.


The main study discussed: