Mind-Muscle Connection: What's the evidence?

[this_dot]

Mind-Muscle Connection​

This was mentioned in a post yesterday and I decided to see what research there is supporting (or not) the importance of a Mind-Muscle Connection.

Belief​

On bodybuilding.com:

What Is The Mind-Muscle Connection?

As you know, movement is controlled by the brain. The first step towards muscular contraction is a signal sent by the brain to your muscles telling them to contract. You might say that the mind-muscle connection (MMC) occurs at something called the "neuromuscular junction". This is where the mind meets the body. The brain releases a chemical neurotransmitter called "acetylcholine" to communicate with muscles in the body.

When acetylcholine is released at the neuromuscular junction it crosses the "synapses" (the tiny space that separates the nerve from the muscle) where it binds to receptors on the surface of muscle fibers. Voila, muscle contraction.

The more you can improve this communication, the more muscle fibers you will recruit. A single muscle head is made up of many individual muscle fibers. By improving your MMC you are actually increasing the number of muscle fibers being recruited when you perform a lift. This results in a better quality muscle contraction and better workout.

Can you change muscular activation by shifting conscient focus?​

A review by Wulf, 2013 tried to clarify the different results of an external focus (i.e., on the movement effect) or an internal focus (i.e., on body movements). This review included a large array of activities, like biceps curls, swimming, rowing, playing piano… They conclude that an external focus is more advantageous for learning and skill performance.

Calatayud et al, 2016 tested 18 men doing bench press with varying intensities and doing it normally, focusing on selectively using the triceps or focusing using the pectoralis. They found that for both the pectoralis and triceps muscles, focusing on using the respective muscles increased muscle activity between 20 to 60 % of 1RM, but not at 80 % of 1RM. The increased activity did not occur at the expense of decreased activity of the other muscle.

The same authors on 2017 did a similar study for push-ups. They found out that that the ability to selectively activate the pectoralis, but not the triceps musculature, was possible during the push-up exercise. However, years of training experience were associated with this ability for the triceps.

Snyder et al, 2012 showed similar results as above for bench-press: trained subjects can alter the participation of muscles (again, triceps and pectoralis) in both moderate and higher intensity (less effective at higher intensities) multijoint resistance training exercises in response to verbal instructions.

Does it work as a long-term training strategy?​

Schoenfeld et al, 2018 compared an internal focus with an external focus training program for 8-weeks in untrained subjects. There’s a good summary of the paper on Schoenfeld’s blog. They showed larger hypertrophy of elbow flexors on the internal focus group (12.4% vs. 6.9%), but no difference on strength gains and no difference on lower limbs hypertrophy.

I couldn’t find anything else on medium or long-term results.

My take-home points​

1. For learning skills, it’s probably more useful to focus on the movement and not on specific muscles.
2. It’s possible to increase activation in a specific muscle by focusing on it, however this becomes harder when the difficulty of the movement is closer to your maximum.
3. This increase activation may enhance hypertrophy, but there’s not enough evidence for now.

So trying to establish a mind-muscle connection: it won’t hurt you, it may help, don’t stress too much about it.

References​

Wulf, G. (2013). Attentional focus and motor learning: a review of 15 years. International Review of Sport and Exercise Psychology, 6(1), 77–104.doi:10.1080/1750984x.2012.723728

Calatayud J, Vinstrup J, Jakobsen MD, Sundstrup E, Brandt M, Jay K, et al. Importance of mind-muscle connection during progressive resistance training. European journal of applied physiology. 2016;116(3):527-33.

Calatayud, J., Vinstrup, J., Jakobsen, M. D., Sundstrup, E., Colado, J. C., & Andersen, L. L. (2017). Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement. European Journal of Applied Physiology, 117(7), 1445–1452. doi:10.1007/s00421-017-3637-6

Snyder, B. J., & Fry, W. R. (2012). Effect of Verbal Instruction on Muscle Activity During the Bench Press Exercise. Journal of Strength and Conditioning Research, 26(9), 2394–2400. doi:10.1519/jsc.0b013e31823f8d11

Schoenfeld, B. J., Vigotsky, A., Contreras, B., Golden, S., Alto, A., Larson, R., … Paoli, A. (2018). Differential effects of attentional focus strategies during long-term resistance training. European Journal of Sport Science, 18(5), 705–712. doi:10.1080/17461391.2018.1447020

 

[lupo]

@this_dot According to article I have read on strongerbyscience website that we should lift as fast as possible to maximize muscular recruitment. This idea, in a mechanical perspectice comes from F=ma formulation. More acceleration equals more force production. With that being said, I still believe we should be consciously activate target muscle group and don't allow power leaks happen throughout the body. So in a summary, lift explosively and lower it in a controlled fashion. Great quote for this is; don't let weight control you, you control the weight.

Edit: Here is the link of the study if you are interested. www.strongerbyscience.com/internal-cues/amp/

 

[noeljack]

@lupo http://akronfitnessandwellness.com/the-truth-about-fast-twitch-and-slow-twitch-muscle-fibers/

“ED: What’s wrong with performing fast repetitions?

JK: So there is no misunderstanding, I want to define what I mean by “fast.” When a barbell, dumbbell, or machine repetition exceeds the muscle’s ability to contract, or the tool is thrown rather than lifted, then that is too fast.

As an example, let’s examine a barbell overhead press being performed by a subject standing on a force plate connected to a recorder. (A force plate is a delicate measuring device that is used to measure changes in force.) If the subject presses and lowers the barbell in a slow, smooth manner, a steady force is recorded throughout the entire movement. On the other hand, a fast movement applies force to only a small portion (usually at the start and at the end) of the repetition.

After the start of a fast repetition, the barbell is actually lifting the subject’s arms (due to momentum). The force applied during the start of the fast movement can often amount to several times the weight of the barbell (a 100-pound barbell for an instant could weigh from 200 to 300 pounds).

Yanking muscles, and that is exactly what is happening, does not build strength. Instead, it exposes the joints, muscles, and connective tissues to danger. Force causes injury, and throwing a weight certainly increases the force.

For the best results from strength training, athletes should perform slow, deliberate repetitions. They should raise the weight smoothly (with minimum acceleration) and lower the weight slowly under full control.

Returning to the example of a barbell overhead press, while standing on a force plate, if you move at a faster pace than approximately 3 seconds on the positive and 3 seconds on the negative, then the bleep running across the scope begins to flutter significantly – which is an indication of too much changing force.

Thus, 3-seconds lifting and 3-seconds lowering seems like a reasonable guideline to follow on each repetition, which is relatively slow when compared to the fast styles that most coaches and athletes utilize.”

 

[lupo]

@noeljack If you replied my comment as opposing idea (which is completely fine by the way), you probably confusing the term explosive or fast lifting with jerking the weight without control at all, like you said ''throwing the weight with momentum". This is not what I am saying nor the article. It says that trying to slow the lift with conscious effort to use mind muscle connection yields less activation if not any yielded benefits. So I agree at any moment of lift, we should be in control completely for safety and also for ensuring we are working the targeted muscle group not the joints or any other muscles etc. Point here was to show that there were no need for slowing the weight less than your ability to lift the weight as fast as possible in a controlled manner. The term fast here doesn't mean throwing the weight or using momentum, it is just relative term for slow tempo reps with conscious effort for mind muscle connection. I hope this makes sense.

 

[noeljack]

@lupo It does thank you for clarifying! I’ll actually read the article now

 

[lupo]

@noeljack You are welcome!

 

[jermyn]

@noeljack I would take that with a grain of salt. Slow speed lifting may have some iffy effects on your gains if you’re going for strength or power.

Also the quoted portion here seems to assume that you can’t or won’t decelerate near the top. You can explode up from the bottom and begin to decelerate when you near the top, which is what most people do anyway.

 

[noeljack]

@jermyn Science indicates the optimum rep speed for muscle hypertrophic and strength is at minimum 1 second up and one second down (or whatever direction the lift is).

If you want the source on that I would have to look it up while I’m off work.

By no means is explosive training needed for hypertrophy or strength. When training for sport, athlete’s muscle fibers are pretty much static, and training explosiveness without a foundation of endurance strength will increase chance of injury. To neglect the stability training that slower reps/ exercises give you is opening the door for injury, and the misconception is a detriment to anyone entering a gym.

 

[this_dot]

@noeljack There is this review by Schoenfeld

I just read the abstract

results indicate that hypertrophic outcomes are similar when training with repetition durations ranging from 0.5 to 8 s.

 

[noeljack]

@this_dot Thank you for the link!!

 

[jermyn]

@noeljack

Science indicates the optimum rep speed for muscle hypertrophic and strength is at minimum 1 second up and one second down (or whatever direction the lift is).

I’d take that with a grain of salt too. If I am thinking about the same study you are thinking, did they match the volume correctly? 10 reps of 100 pounds on a 1 second up and 1 second down is 1000 pounds of total tonnage with 20s of time under tension. That 10 reps of 100 pounds with 3 seconds down and 1 seconds up is 1000 pounds of tonnage and 40 seconds of time under tension. But I think the study you might be referencing there made the mistake of having them use different tonnages and loads. So I’d take it with a grain of salt and be careful.

By no means is explosive training needed for hypertrophy or strength.

This is something we can be sure is true.

To neglect the stability training that slower reps/ exercises give you is opening the door for injury, and the misconception is a detriment to anyone entering a gym.

Gotta be careful here. In some cases, yes. In others, no.

 

[noeljack]

@jermyn I’ll be sure to do some more reading to look into your perspective. Thanks for the feedback

 

[jermyn]

@noeljack Thank you! And I don’t think it’s not true. Just maybe sometimes not. I’m not really sure.

 

[lectiodivina]

@jermyn

Just maybe sometimes not.

Everyone needs to read this and reflect on it. One size does not fit all. One movement pattern is not safest in all situations.

The experiences we all have with movement and its associated strengths is extremely valuable. The interpretations that oversimplify our experiences are not.

Studies by definition are overly constrained on one thing. Don't use studies as some kind of silver bullet because you will likely never move and work exactly the way the subjects in the study moved and worked.

And last, look at the size of the group being studied. 18 men. (Where are the women?) 18 is not statistically significant. Go to any gym and you'll observe more than 18 varieties of body types, motion styles, AND goals. Don't put so much trust in 18 men doing two exercises being a meaningful guide for your own success.

The one cool observation in these studies is how more experienced athletes can turn off different muscle sets. This is what Tai Chi does, even though practitioners don't describe it in those terms. If your goal is quickness of motion, then patterning your muscles to relax except for those few muscles required to execute a motion will achieve that goal.

 

[jermyn]

@lectiodivina Yeah the first thing is making sure the science is sound and often, it is iffy. Low sample sizes and often not the same amounts of volume. And then you have to consider that everyone is different so it’s lke even the best advice is probably completely wrong for anfew peiole, at least.

 

[koolsheep]

@noeljack An other science backed claim that crossfit is shit.

 

[shpchvr]

@lupo I think it kinda depends if you are going for strength or hypertrophy. If you want to go for strength, move as much as possible and generate as much force as possible. If you want to go for size, you need to activate and fatigue that specific muscle. Bonus would be that lower weights reduce your risk of injury.

 

[lupo]

@shpchvr The term fast doesn't mean you are not fatiguing the muscle or not engaging it. It is a relative term for slower tempo reps with conscious effort of mind to muscle connection. You are still controlling the weight and still engaging, fatiguing the relevant muscle. Risk of injury happens when you lift without control or too heavy, not lifting as fast as possible in a completely controlled fashion. Please look my reply above where I have explained to another user what this article really is saying and the term fast means.

 

[shpchvr]

@lupo I agree with what you are saying, and can clarify my point a bit.

Let's take a heavy row for example. When you try to move a heavy row with explosive speed, it will fatigue several muscles, and they will all work together in a "natural" way. When you move a lighter row slowly, while focusing on just squeezing the lats, your lats specifically should be more fatigued by the end of the set, even if your body as a whole is not. Less effective for overall strength, more effective for hypertrophy of the lats specifically. Also, you can replace rows and lats for bench and pecs...

On injury risk... I was just assuming that a slower rep with a strong focus on mind-muscle, will inherently be at a lower weight. I find it harder to imagine someone getting injured on a slow (and likely lighter) bench with a focus on squeezing the pecs, than it is to imagine someone getting injured with medium to high weight exploding a full upper body force to make the bar fly through the rep.

Again, good for strength, not necessary for hypertrophy. Which should have been my point to being with... "not necessary for hypertrophy" but definitely helpful for strength.

 

[lupo]

@shpchvr I understand you mate but again, explosive doesnt mean using momentum or swinging the weight. You are still in complete control, and its relative term used for comparing slow reps with intentional focus on mind muscle connection. Also you can squeeze muscle at top, for rows, even when iniating movement faster than slow tempo reps. That squeeze is all about control and using the correct weight for yourself, fast or slow you could still do that. Not feeling muscle is about not properly engaging target muscle and using weight heavier than you should. There is no good or bad for both strength and hypertrophy in this case. Even if you train for strength you should be in complete control and use correct muscles. Powerlifters benefit as much as bodybuilder here, but weighlifters are not due to their lifting style inherently being explosive manner (using momentum).