Discussions about mind-muscle connection have been around for decades. Bodybuilders talk of flexing and squeezing the muscle rather than just lifting the weight from A to B, claiming that growth is best achieved when you maximize the “feel” of the muscle. This approach has been embraced by the gym-bros and mocked by the evidence based keyboard warriors but, who is right? Does mind-muscle connection build more muscle?

Fortunately, we don’t have to rely solely on the anecdotal observations of old-school bodybuilders, gym-bros, or the naysayers anymore. Leading researchers have begun to investigate the impact of the mind-muscle connection on muscle growth and their findings offer some key takeaways that could have vital practical implications on how you approach your training.

Researchers describe your focus during resistance training as attentional focus, which can then be broken down into two types: internal attentional focus and external attentional focus. Lifting to create a good mind-muscle connection is classified as internal attentional focus, wherein the lifter focuses internally on the working muscle throughout every rep. On the other hand, lifting to move weights from A to B is classified as an external focus. In this condition, the lifter is primarily concerned with the implement they are lifting, and moving it from the start to the end of each rep as efficiently as possible

To illustrate this point, some examples of an internal focus are:

Examples of external focus:

Related: 7 Ways to Improve Mind-Muscle Connection

The research to date indicates that an external focus seems to be superior for “performance” metrics like movement efficiency, force, and power production. If you want to lift as much weight as possible or move a weight fast then an external focus will have better results than an internal focus.

When a powerlifter steps foot on the platform trying to hit a PR they will be best served thinking of cues like driving his hips through to lockout a deadlift. Not contracting their hamstrings to extend their hips.

While there is conclusive evidence that an external focus is optimal for performance outcomes, the debate for muscle growth is more nuanced. Three recent studies explore this topic of discussion.

The first study compared muscle activation on bench presses during different lifting tempos. Interestingly, during fast explosive reps an internal focus did not increase muscle activation. It seems that performing reps explosively already causes peak muscle activation levels. However, during slower reps an internal focus was found to have greater muscle activation than an external focus. In this case, it seems that the mind-muscle connection was able to compensate for the loss of activation created with explosive reps. So, if size is your goal and you’re using slower rep speeds it seems an internal focus will serve you well.

Another study examined the difference between internal and external attention on leg extensions. They found that when performing the same number of reps, muscle activation was higher with an internal attentional focus.

While this study showed increased muscle activation in the quads as a whole, it also indicated it was not possible to specifically target an individual muscle within the quads. For example, trying to boost activation in just the vastus medialis actually just resulted in an increase in the three other quad muscles. So, while we can use the mind-muscle connection to target muscle groups we probably can’t use it to develop specific regions of a muscle.

One question this study left unanswered was if participants were performing to failure. If not, it’s possible an external focus would allow for more reps to be performed, a longer time under tension, and perhaps activation levels similar to an internal focus once failure is hit (or even in the few reps before failure).

While the last paragraph seems like a case for external focus it is worth considering that getting the most from the least is a very wise move when it comes to long-term progress. An internal focus might, therefore, allow you to stimulate a muscle with fewer reps or less weight. This will reduce the wear and tear on your joints and reduce the systemic fatigue generated by your training. Less systemic fatigue means you have more capacity to train other muscle groups and maximize your growth across all muscle groups.

An interesting point to consider is that, on isolation exercises, an internal focus appears superior. Meanwhile, on compound exercises like bench presses, lifting explosively allows for more weight to be lifted and high levels of muscle activation.

A third study adds a great deal to the mind-muscle connection and muscle growth debate. This 8-week training study measured muscle growth at the beginning and end of the study. This is extremely informative as it gives us a measure of muscle size change as an outcome when comparing internal versus external focus. All the previous studies have just measured muscle activation and left us to speculate as to how that would play out in terms of muscle growth. So, this study gives us some genuinely concrete muscle growth data to analyze.

The other great thing about this study is that the training involved participants performing biceps curls and leg extensions to failure. This is much more representative of how we train in the gym so it provides transferable practical tips for us to apply to our own training. Even better, they matched volume between the internal and external focus groups. The fact that both groups did the same total workload means we can actually begin to analyze the impact of training with an internal versus external focus on muscle growth.

The results of this study showed greater gains in strength for the external focus group. This is not a surprise and supports previous research on attentional focus and performance outcomes. Hypertrophy, however, was greater in the internal focus group. Specifically, an internal focus resulted in almost double the muscle growth of the external focus group. The participants using an internal focus grew their biceps by an average of 12.4% compared to 6.9% in the external focus group.

The impact of an internal focus was not so significant in the quads. The authors of the study speculated that this may have been due to subjects finding it easier to create a mind-muscle connection with the biceps than the quads. After all, you can ask any kid to flex their biceps and they’ll throw up a super-cute front double biceps pose. Ask them to flex their quads and you’ll just get a confused look.

The authors continued to say that we use our upper extremities for fine motor skills (e.g. writing, drawing, using our smartphones) more than the lower extremities, which tend to be used for gross motor skills (e.g. walking, running, jumping). Because of this it is possible we are more aware of our arm muscles compared to the muscles of the legs. Consequently, the average person can get a better mind-muscle connection with their arms than their legs. Because of this, the participants were not able to maximize the benefits of an internal focus on leg extensions. Also worth noting, the participants in this study were untrained so an experienced lifter would likely be able to develop a better mind-muscle connection on leg exercises and see enhanced growth.

Based on the research it seems that the mind-muscle connection increases hypertrophy in isolation exercises. When it comes to compound exercises we still need more research to be certain. Personally, I’ve taken the approach of pursuing performance on the big lifts and a mind-muscle connection on isolation work. When squatting, benching, deadlifting, or doing chin ups,  I use an external focus and strive to lift the most weight possible as explosively as possible for the target rep range. With isolation lifts, I let weight take a backseat and focus on creating the greatest mind-muscle connection possible.

It is still possible, and arguably just as important, to strive for performance progression from session to session on isolation lifts. You can achieve this by getting another rep in at a given weight, or by adding a bit of load for the same number of reps. However, this should never be done at the expense of form and maintaining a great mind-muscle connection.

Here is a final tip to help you get the most from applying the mind-muscle connection to your training…

In an effort to improve mind-muscle connection, most trainees approach it as a bottom up problem. They focus on doing loads of reps and creating a burning sensation in the muscle. By moving light weight in high repetitions, trainees are eventually able to feel the muscle working. This sensation is largely attributed to an increase in the acidity of the muscle after the release of metabolites, following multiple contractions. They are actually using an external approach (moving the weight from A to B multiple times) to eventually create an internal feedback.

However, treating the issue from a top-down perspective is better. Rather than doing loads of reps and hoping to eventually feel your muscles burning you should think about directing the contraction from rep one.

Making the muscle work from rep one is far more efficient and can be done if you purposefully focus on making the muscle contract to create movement. Try it with biceps curls. Rather than simply flexing the elbow and waiting for the biceps to begin burning you should purposefully flex the biceps to make the elbow flex. When you do this, you can feel the biceps on a much deeper level from the very first rep.

Having some basic anatomy knowledge will help you do this. If you know where muscle originates (starts) and inserts (it’s furthest attachment from the centre of the body) then, you just have to focus on contracting the muscle to bring those two points together. This is much more efficient than haphazardly swinging weights around in the hope of eventually getting some biofeedback that will help develop your mind-muscle connection.