The mind-muscle connection

Here is a brief summary:

1. Many bodybuilders believe in the mind-muscle connection: mentally activating a muscle. Others believe that if an exercise is performed with good form, the right muscles will do their job automatically.
2. The author decided to test (using EMG) whether load, cadence and form of exercise execution dictate muscle activation, or whether it is possible to steer the neural drive towards some muscles and away from others.
3. The surprise of the study was not that it showed that you can mentally activate a muscle, but how big a role our mind plays in getting our muscles up to speed.

Contract your brain

Bodybuilders have long referred to the mind-muscle connection and they typically recommend that novice exercisers spend time contracting their muscles independently of training and learning how to correctly activate their muscles against resistance.

On the other hand, there is a subset of trainers and physical therapists who believe that if an exercise is performed with seemingly good form, the correct muscles will automatically do their job and that it is not necessary or even possible for an exerciser to mentally alter their muscle activation.

Which of these camps is correct?

Do load, cadence and form dictate muscle activation? Or can exercisers mentally control the neural drive toward certain muscles and away from others even when using the same weight, tempo and mechanics by simply focusing their attention on the target muscle?

For some, the following experiment will seem like one of the most obvious experiments they've ever seen. You may think it's old hat, especially if you've been involved in bodybuilding for some time. But for others, it will open their eyes and give them an insight into the role of the brain in muscle activation.

Methods

We decided to get to the bottom of this discussion by conducting a pilot experiment. Basically, we performed a series of different upper and lower body exercises, using an electromyograph (EMG) to study muscle activation. While performing the exercises, we focused our attention on either activating a specific muscle or not activating a specific muscle.

We used different exercises for the lower body: squats, Romanian deadlifts, hip thrusts and back extensions. We used a 135-pound barbell for squats, Romanian deadlifts and hip thrusts, while for back extensions we only used our own body weight.

Our intention with each exercise was not to use the gluteus. In the case of squats, the intention was to target the quadriceps instead and in the case of Romanian deadlifts, the intention was to target the hamstrings instead of the gluteus. When we performed the tests again afterwards, we deliberately tried to maximize the use of the gluteus.

We also used four different exercises for the upper body - two pushing exercises and two pulling exercises. We used push-ups with our own body weight and bench presses with 135 pounds for the push muscles of the upper body. For the first exercise we focused on our pecs and for the second exercise we focused on our triceps.

For upper body pulling exercises, we used bodyweight pull-ups and inverse bodyweight rowing. Both exercises were performed in two different ways - first with an emphasis on the latissimus and then with an emphasis on the biceps. We opted to stick with lighter weights as we felt this would improve the ability to control neural drive compared to using heavier weights, if such a thing was even possible.

In addition, we have long observed professional bodybuilders moving seemingly very light weights while contracting their muscles very hard in an attempt to subject the target muscle to maximal tension and metabolic stress. So using similarly light weights should allow us to determine if this method has merit.

Results

We found that advanced exercisers can indeed direct their neural drive towards and away from certain muscles without significantly altering the form of exercise execution. The table below shows our average data regarding muscle activation. Of course, you can save yourself the trouble of analyzing the results yourself and simply read the following section.

Lower body exercises	Gluteus Maximus	Biceps Femoris	Vastus Lateralis	Lumbar erector
Squats Quadiceps Focus	10.61	11.19	109.67	48.73
Squats gluteus focus	25.30	12.78	94.33	54.63
Deadlift leg curl focus	9.13	21.07	30.80	60.67
Deadlift gluteus focus	32.13	22.67	35.97	54.33
Hip thrust without gluteus focus	20.90	6.80	33.43	70.83
Hip Thrust with gluteus focus	52.67	18.40	52.60	61.53
Back extension without gluteus focus	6.05	43.63	2.17	52.53
Back stretches with gluteus focus	38.13	52.70	2.69	47.87

Upper body press exercises	Upper chest	Lower chest	Front shoulder	Triceps
Push-up chest focus	60.47	47.10	55.33	63.30
Push-up triceps focus	51.77	23.74	51.13	90.77
Bench press chest focus	64.90	54.77	49.77	63.43
Bench press triceps focus	58.47	33.23	50.73	71.77

Upper body pulling exercises	Lat	Rear shoulder	Middle trapezius	Biceps
Pull-ups Latissimus Focus	59.73	67.33	68.30	44.10
Pull-ups biceps focus	59.17	73.07	50.50	68.70
Inverse rowing latissimus focus	82.10	82.57	94.73	31.33
Inverse rowing biceps focus	66.60	75.13	62.27	71.30

Discussion

As you can see from the table, there is clear evidence of a mind-muscle connection and this phenomenon is more evident in certain muscles than others. Perhaps the most illuminating result of this study is that experienced exercisers can perform a back extension using their own body weight - which for an average athletic male requires 235 Nm of torque at the hip - moving from full hip flexion to full hip extension while barely using the gluteus.

When they consciously tried not to use the gluteus during back extension, gluteus activation on the EMG reached only 6% of MVIC (maximum isometric contraction). However, when they consciously attempted to use the gluteus, the EMG value increased to 38% of MVIC!

The activation of the gluteus during the hip extension exercise was highly dependent on the mental focus of attention. During squats, Romanian deadlifts and back extensions, gluteus activation could vary significantly depending on whether the subjects tried to activate or not activate these muscles, and gluteus activation was quite low when the subjects focused on activating the quadriceps during squats and on activating the leg flexors during Romanian deadlifts. In fact, it seems to be quite difficult not to use the quadriceps during squats, not to use the hamstrings during back extensions or not to use the gluteus during hip thrusts.

As for the upper body press muscles, activation of the lower pectorals was quite low when subjects focused on the triceps during push-ups, but when they focused on the pectorals, triceps activation was much lower. In addition, it appears to be easier to mentally control muscle activity during push-ups compared to bench presses.

In the pulling exercises, the activation of the middle trapezius and biceps varied significantly between trials. Latissimus activation hardly changed during pull-ups regardless of the focus, but changed significantly during inverse rowing. The activation of the biceps and middle trapezius seems to depend strongly on whether the focus is on the latissimus or the biceps during the pulling exercises and it seems to be easier to control the muscle activity during inverse rowing compared to pull-ups.

We deliberately did not focus on direct activation or minimizing activation of lumbar erectors, upper pectorals, anterior shoulder muscles and posterior shoulder muscles, which explains that their activation was more consistent compared to gluteus, lower pectorals, triceps and biceps.

Practical application and conclusion

Based on this experiment, we conclude that advanced exercisers are able to direct the neural drive towards and away from certain muscles - at least at lighter weights.

In 2012, researchers Snyder and Fry found that verbal instructions were effective in controlling muscle activation with lighter weights in the bench press, but this was not the case with heavier weights. Similarly, a number of studies have investigated the effects of internal focus of attention (focusing on muscle groups while performing movements) and found that individuals may preferentially activate certain muscles, such as the abdominals, latissimus and gluteus, depending on the task.

One study, for example, showed that abdominal dancers were able to activate their upper and lower abdominal muscles in complete isolation from each other, suggesting that targeted activation of muscle groups becomes easier with exercise. There is research that is almost 20 years old that provides evidence of a mind-muscle connection in shoulder stabilizers.

We believe that this experiment shows that the idea that "if it looks right, it is right" is incorrect - at least when it comes to training with light weights. For example, as we have already explained, it is perfectly possible to extend the hips while the gluteus is barely activated during the back extension.

The form of the exercise execution must be sound, but simply observing the movement from the outside will not fully tell you what is really going on inside. The underlying muscles need to be activated at the correct levels and combinations during the movement for optimal performance and these levels and combinations of activation will likely differ depending on whether the goal is to develop maximal strength, maximal endurance or maximal activation.

The literature is unanimous on the fact that an external focus of attention (focusing on something outside the body) will produce better demonstrations of strength, endurance and accuracy. If you want to move a maximum weight in the bench press, then you should not focus on maximum activation of your pecs or triceps, but rather on moving the bar away from your chest as explosively as possible.

Furthermore, this experiment suggests that bodybuilders were indeed right all along - the mind-muscle connection is a real phenomenon that influences neuromuscular dynamics during resistance training. It is logical to assume that the mind-muscle connection could influence hypertrophy gains to a significant degree, but this has yet to be proven in other research.

In order to confidently recommend that exercisers prioritize the mind-muscle connection, we need to investigate whether bodybuilders can control neural drive even when using heavier weights and whether focusing attention on activating specific muscles during an exercise actually leads to greater hypertrophy adaptation over time. In the meantime, you can consider experimenting with a few different methods:

1. Try what Mel Siff calls "no-load training" by contracting muscles independently, like bodybuilders do during poses.
2. Perform a low-load activation before heavy weight training or between heavier sets to see if this improves your performance.
3. Perform heavy training with an external focus of attention, but also perform lighter training afterwards with an internal focus of attention where you concentrate on trying to activate the target muscles.

By Bret Contreras

Source: https://www.t-nation.com/training/mind-muscle-connection-fact-or-bs