Bodybuilding – An Unnatural Act
Perhaps it’s the contrarian in me who fondly refers to bodybuilding is an “unnatural act” of sorts: Repeatedly picking up and lowering a load for the sake of producing a “muscular callous” (i.e., an enlarged muscle) doesn’t seem to very utilitarian from an evolutionary perspective. On the other hand, we’re social animals, and muscularity has value as a sexual attractant(25). Sex appeal notwithstanding, even the notion that muscle growth is a truly adaptive response to strength training(60) has been called into question by scientists: It’s even been suggested that size gains are just along for the ride during what is mainly a neurologically-rooted adaptive process(39).
It’s All About the Stimulus
Still, you and I are here for the gains and those of you struggling with lagging muscle groups may recognize a salient characteristic of the muscle growth stimulus: Some muscles seem to activate, pump up and thus grow really easily, whereas others have unique recovery needs and may require much more prodding in terms of variety, intensity, volume and/or frequency of stimulus. [I’ve written about this in my Be Your Own Bodybuilding Coach™ book(57).] In summary, bringing up “weak” muscle groups means (at the very least):
- Picking the right exercises (for you) to target the muscle and cultivating the Mind-Muscle Connection (which this article is all about).
- Paying special attention to frequency of training, exercise sequencing and rep / set schemes.
- Ensuring volume and recovery (time, diet, supplementation, etc) are in their proper place.
For the sake of this article, though, let’s start by defining the Mind-Muscle Connection (MMC). I put forth that the MMC is “the neurological capacity to perform (a) resistance training movement such that the targeted muscle(s) – the one(s) you want to specifically train – are the muscle(s) that are indeed the primary movers, heavily involved (ensuring a both mechanical load and metabolic stress) during the exercise, and ideally even the “weak link” such that exercise performance overall (reps with a given load or loading scheme) is limited in particular by the physiology (force output) of the targeted muscle(s).” In short, the Mind-Muscle Connection is about making the target muscle the central focus of the stimulus of a given exercise such that it gets the brunt of the stress and thus the lion’s share of the stimulation when performing that exercise. This of course, would be done by focusing mentally on the target muscle during the set by visualizing and “feeling it” (proprioceptively)(28, 41, 58, 59, 64). (Feel free to check out my article at www.elitefts.com on practicing mental imagery for more on this topic: https://www.elitefts.com/education/mental-imagery-techniques-can-they-make-you-bigger-and-stronger/.)
Can and Does the MMC make a Difference in One’s Physique?
Think about it for a second: The MMC really is at the core of the pursuit of bodybuilding, whereby one literally builds and specifically sculpts one’s musculature. Obviously, weight training produces growth specific to the trained musculature and bringing up weak muscle groups is a function of how one trains them. Even exercises that produce the same motion about a joint, anatomically speaking, are not necessarily created equally in terms of activating target muscles. Just imagine the quad development of someone who only performs knee extensions compared to the quads of his identical twin who trains his thighs with a wide variety of exercises (squats, hack squats, sissy squats, leg presses, etc.). [I refer you to Per Tesch’s books “Target Bodybuilding(62)” and “Muscle Meets Magnet(61)” for magnetic resonance (MR) images showing the wide range of the differential activation patterns that we bodybuilders have been aware of for decades now.] It’s also known that muscle growth is non-uniform along it’s length (often greater in the middle portion of a muscle’s belly)(1), and this relates to it activation pattern across the muscle belly(65). We see this differential recruitment very clearly, for instance, in multi-headed muscles like the gastrocnemius of the calf where both MR images and integrated EMG measurements demonstrate this kind of spatially-specific muscle activation(35, 53). So, how a muscle is activated in training determine how and where it grows.
Mind-Muscle Connection: Hacking Our Own Noggins
Putting the load on a target muscle versus being focused on purely on performance (e.g., moving a heavier load for more reps) is an example of an “internal” (within the body) vs. external (outside of the body) attentional focus(66), respectively. Unlike the powerlifter or Olympic lifter where improved performance on the lifting platform is the, the bodybuilder’s physique (demonstrating enlarged musculature) is the measure of success. Form takes precedence over function in this regard when bodybuilding, and one must keep this in mind especially when “chasing the log book” during progressive overload-focused training. [Because of this conundrum, I intentionally include “Set Types” in Fortitude Training® (www.fortitudetraining.net) that are progressive overload focused, using exercises where one feels the target muscle easily (“Loading Sets”), as well as higher rep sets where the trainee has freedom to engineer exercise variation and rep schemes, including partial reps, that facilitate a mind-muscle connection. I call this latter Set Type “Pump Sets.”]
Creating a strong MMC is thus vital to the long, arduous process of gaining muscle size. It makes sense that the body would prefer a more economical means of adapting than the energetically expensive process of adding muscle tissue. We see this in that strength gain outpaces(32) and precedes(44) muscle growth, and, at the very start of training, metabolic adaptations(17, 42, 56) are initiated to reduce fatigue and protect against muscle damage, long before muscle growth is noticeable.
Neurologically, the motor areas of the brain and spinal cord are hard-wired to with specific strategies to activate muscle during resistance exercise. Generally speaking, motor units (a neuron and the muscle fibers it innervates) are called upon according to the very well substantiated Henneman’s size principle(18, 29, 30, 38). This means that motor units are recruited in a predictable, orderly fashion, from low to high threshold motor units, depending on the amount of force (and speed/power) required and the state of fatigue of a muscle. Unnatural act or not, the nervous system uses the size principle and other complex neural tactics during tasks like a normal set of reps where one is simply repeatedly lifting and lowering a load:
- There are different activation strategies in the brain during strength vs. fatiguing tasks(52).
- Muscle lengthening (eccentric), isometric and shortening (concentric) actions are differentially controlled via neuronal excitability(19).
- To prevent fatigue, the nervous system uses the size principles in addition to even more complex strategies(49), including rotating among motor units to spread the work / load out over more muscle tissue(3).
- During a phenomenon known as “muscle wisdom,” the firing rates of motor units decrease in accordance to fatigue-related feedback, thereby preventing rapid-fire neuronal activation to a muscle in which fatigue has slowed it’s contractile properties(5-7, 26). (See below for more on muscle wisdom in the context of pre-fatiguing target muscles.)
Schematic of the Muscle Force-Velocity Curve during voluntary contractions and those of isolated, electrically stimulated muscle – showing how muscle is inhibited during lengthening vs. shortening contractions as a function of speed of contraction. Based on a figure By Mokele (talk).HCA at en.wikipedia. Later version(s) were uploaded by Gciriani at en.wikipedia. [Public domain], from Wikimedia Commons., Figure also based on voluntary muscle performance from two studies(20, 45).
Evidence for a Mind Muscle Connection
So, given all the plethora of unconscious motor control strategies at work when we’re lifting, we’re fighting a bit of an uphill battle, if we’re to purposefully control how and where muscle loading goes, i.e., have a strong MMC. Don’t forget though: These are voluntary muscle contractions in the gym, so we obviously have some say-so as to how and which muscles are activated. Indeed, it’s the voluntary nature of the resistance exercise (our brains are running the show here) that we’ll rely upon to purposefully, intentionally create the mind-muscle connection. The question is then: How easy is to have a strong MMC and what are the best ways to do it?… Let’s take a look…
Mastering the Mind-Muscle Connection
As I insinuate above, the conundrum of the MMC is that it requires internal attentional focus (on the target muscle), applied when performing the lifting task, which de facto also requires some amount of external attentional focus on lifting and lowering the load. (We’re lifting weights, but the purpose is actually just to stimulate the muscle, more so than lift and lower the load per se.) Fear not: A good MMC is not beyond our reach!
Electromyography (EMG) confirms that when subjects are asked to focus either on the triceps or the chest (pectoralis major) musculature during the bench press, they can shift activation to one or the other muscle groups. This is easily accomplished with lighter loads (<80% of a 1 repetition maximum; 1RM), but when loads are in the 8-10 rep max (80%1RM) range, the MMC is lost(11). This makes sense to some degree, because when one nears a true 1RM, simply lifting such a load requires that as much muscle – all of those involved in the exercise and not just the target muscle – be engaged. In other words, lifting near maximal loads precludes a MMC, because one simply must call upon (nearly) all the available musculature – not just the target muscle(s) – to perform the lift in the first place! STOPPED HERE! Similarly, when asked to move the bar “ballistically,” the MMC may be lost(12). Here there is both an the external attentional focus on high effort movement (in all muscles involved) that perhaps disallows selective activation ala the MMC.
Obviously, it’s verbal instruction and the conscious effort that makes the difference in the MMC, and this can be seen in studies where researcher instructed their subjects during back / lat(55), chest(54) and delt/shoulder(46) exercises. Additionally, it’s possible voluntarily reduce the activity co-activated muscles such as the traps(47) during shoulder exercise. With instruction, beginners can even exert substantial MMC over the oblique vs. rectus abdominis (“6 pack”) muscles during abdominal exercise (“trunk curls”)(34).
When it comes to focusing on the triceps or the pecs during pressing movement, with experience (practice) comes an even better MMC(13) (r=0.51 for ∆EMG signal vs. training experience). This was a general finding in this study(13) where bench press (the classic chest-building exercise) was tested, which may require greatest triceps activity during maximal efforts(36) (as many powerlifters would agree). Interestingly, the two most experienced subjects (>20yr training experience each) actually showed tremendous disparity in the ability to intentionally use the triceps during a 1RM effort. The authors didn’t discuss these two data points in particular (found in Figure 2), but I might speculate that the experienced lifter who had a hard time with a triceps-oriented MMC during bench pressing may have suffered from a contextual interference effect(40). In other words, its possible that, because he had spent so many years using the bench to build his chest (developing that specific MMC), he simply couldn’t transform the bench into a triceps exercise in the lab.
Mind-Muscle Connection: Cues n’ Hacks…
Other than just being told to do so and, of course, making the conscious effort, how else can one manifest a better mind-muscle connection?… Can a stronger MMC be cued somehow?… Here are a few more thoughts:
- When asked to perform a hip extension “glute lift” (a kind of unilateral reverse hyper) using the gluteal musculature, rather than the hamstrings, subjects were able to perform this task, and did so by activating the glutes just before the hamstrings(37). This suggests that initiating the movement with the target muscle may favor a better MMC.
- Naturally, including a warm-up that literally constitutes practicing a strong MMC (with light loads and in a controlled, non-ballistic fashion – see above) should help build the skill of a good MMC.
- Similarly, perhaps due to it’s role in lower body kinematics(43) a gluteal warm-up may improve squat / countermovement jump performance(15, 16) by facilating greater activation(48), although this is not a universal finding(14).
- Similarly, one could also attempt use an isolation exercise to create post-activation (force output) potentiation (PAP) in the target muscle that equates to greater force output during the compound lift. PAP may last for many minutes and can be brought on by a “conditioning contraction” (a bit different than a normal warm-up) that is as simple as a single short (5-10s), non-fatiguing, but high intensity (75+%) effort (isometric will do)(31, 63, 67). This is not truly a MMC strategy, but could have the (same) effect in shifting the loading of a compound exercise towards the intended musculature, and perhaps provide biofeedback (vis-à-vis greater force production in the target muscle) and facilitate acquiring the MMC skill.
- Although not borne out well in the scientific literature, “touch training” or tapping / stroking the skin overlying and mechanically stimulating (tapping or pressing on) the target muscle is a common biofeedback strategy employed to help “feel” the target muscle. Skin stroking has been shown to facilitate patellar tendon (quadriceps)(10) and lower body reflex arcs(4), so there may also be a lower motor neuron involvement in this approach.
A simple schematic of an alpha-motoneuron (from https://commons.wikimedia.org/wiki/File:Motoneuron.png)
A Note On Pre-Fatiguing / Pre-Exhaustion
Pre-fatiguing (aka “pre-exhausting”) a target muscle (e.g., the pectoralis major) by performing an isolation exercise immediately preceding a compound exercise (e.g., some sort of chest press) is a common way to focus training load on a target muscle(23, 24). However, I’m aware of only one(21) somewhat controversial(22, 50) training study (using novice trainees) examining pre-exhaustion which found no effect on strength gain. (Measures of muscle size were not reported.)
On the other hand, several studies have used EMG to examine muscle activation of a pre-fatigued muscle during compound exercise. Using a “root mean square” EMG measurement, expressed relative to a maximal measurement in the unfatigued state; RMS, one research group found that pre-fatiguing of the quads resulted in greater activation during low load leg pressing efforts(33). However, other studies found no change(9, 27) or a reduction(2) in RMS EMG of the pecs during heavy (10RM) sets taken to momentary muscular failure. In these latter cases especially, pre-fatiguing substantially reduced reps performed (e.g., reducing a 10RM set into a 6 rep set to failure when pre-fatigues). This suggests, of course, that pre-fatiguing impaired performance, presumably because it had the intended effect of shifting the loading to the now (pre-)fatigued, targeted muscle. Notably, these equivocal EMG results may be polluted by the phenomenon of “muscle wisdom” (see also above), whereby afferent information slows neuronal firing rate to more appropriately match muscle fatigue(5, 26). Due to this effect, EMG RMS signal strength declines over time during maximal efforts(8), so comparing pre-fatigued EMG values to those obtained in the unfatigued state may do little to inform of the true relative load placed on a single pre-fatigued muscle during a compound exercise. My thought is that pre-fatiguing has value, and this is why I include it in Fortitude Training® (www.fortitudetraining.net) as a tool for focusing muscle loading (during “Loading Sets”) and, in my experience, entraining a better MMC.
Example of a deltoid EMG signal (from https://commons.wikimedia.org/wiki/File:EMG_muscle_deltmed_-_milling.jpg)
Practical Tips and Tricks for a Better Mind-Muscle Connection
Based the findings and musings I’ve presented in this article, here are some practical ways you can target weak / lagging muscle groups, ensure focused loading on target muscles during (smartly chosen) compound exercises, and better establish your Mind-Muscle Connection:
- Initiate movements with the target muscle first, moving slowly if needed to ensure this.
- Per the above, perform movements in a controlled fashion so as to maintain the MMC.
- Keep your training loads below about a 10RM if you have trouble with the MMC on a given exercise.
- Use isolation / “activation” exercises as warm-ups and consider using a post-activation potentiation or pre-fatiguing strategy (see above).
- Perform perfect repetitions: Swallow your ego and restart progressive overload at a lighter load if needed.
- Be sure to engage the target muscle during eccentric (lowering / negative) contractions, as well. (This may even mean doing a bit of a “squeeze” at the “top” of the movement, i.e., the transition from concentric to eccentric contraction, to be sure the target muscle is engaged when lowering the load (during eccentric contraction).
- Perform static holds and partial repetitions in the range of motion where you best feel the MMC.
- Practice your posing, being sure to contract and connect with the muscles where you lack a good MMC.
- Pick the right exercises that lend themselves to a good MMC. This can mean varying loading curves with bands and chains, adjusting your stance and grip width, using different cable attachments that help with the MMC, and finding exercise variations that suit you. (For some exercise variations you might not have seen, check my Instagram account: @fortitude_training.)
Here are some muscle-specific suggestions that may also help:
- Chest: Keep your chest high / arched, with scapulae retracted, driving your hands / palms together when pressing (as if doing a fly, even if using a bar / machine that doesn’t permit this).
- Deltoids: Pre-fatigue and keep the elbows held posteriorly on overhead presses (shoulder flexibility permitting) to better engage the middle head of the deltoid.
- Triceps: Avoid chest involvement by keeping elbows close to the body / midline.
- Back: Use these cues to disengage the arms and focus on the back musculature: Your hands are hooks (don’t grip the handles / bar), your elbows are hinges (don’t pull with the biceps) and drive the elbows back and down (depending on the angle of pull).
- Biceps: Where possible and safe (and you won’t drop the weight!), try using a loose / open grip to disengage the wrist flexors during elbow flexion.
- Quads: Pre-exhaust before compound movements, slightly elevate the heels (given no knee pain) during squatting movements, and use a close stance (feet low on the leg press plate), pressing off the forefoot.
- Hams: Plantar flex during ham curls to disengage the gastrocnemius as a knee flexor.
- Glutes: Pre-exhaust, use a wide, hips externally-rotated stance with a good bit of hip flexion on squats and leg presses, and perform isolation exercises to learn how to engage the glutes and develop a strong MMC.
- Calves: Pressing off the “ball” of the foot (1st metatarophalangeal joint), or with the feet pointing out(51), seems to better engage the medial gastrocnemius. Be sure to use a full range of motion!
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