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Functional Muscle vs Aesthetic Muscle – Debunking Big Muscles and Hypertrophy

Big man in a suit or armor, take that off, what are you?”

-The Avengers

What are you under those giant, intimidating muscles? Powerful? Nimble? Genius, billionaire, playboy, philanthropist? Big muscles are often misunderstood; “They aren't functional muscles” is the general consensus.

The cliché story of the big bodybuilder who can't run a mile or wipe his own behind has been passed around to everyone for generations, it seems. But what is the real story behind having big muscles? What sets them apart from the strong guys with leaner muscle? Can big muscles be functional, and how?

To understand big muscles, we first have to understand muscle growth. When you exercise, your muscles get a stimulus relative to the intensity of your training. Your body registers that as fatigue, and immediately works to repair your muscles. 

This is the important part: your muscle filaments, or your myofibrils, are the actual muscle fibers that control strength. This is what gets repaired after your workout.

The protein density in the myofibril is what contributes to your strength, which is why it's important to rest and refuel (about 240 grams of protein a day) after an intense workout for optimum strength. The myofibrils get thicker, but don't contribute greatly to muscle size as much as they do to muscle strength. Functional muscle is myofibrillar growth.

What contributes to the size is the sarcoplasm: the glucose heavy fluid outside of the myofibril. The amount of sarcoplasm in the muscle grows, as in bodybuilding, to accommodate impending stress from high volume workouts. Essentially, the muscle is storing up energy for the next workout.

However, there are no contractile cells in the sarcoplasm, so while sarcoplasmic growth adds a lot to size, it DOES NOT add to strength. The only purpose of sarcoplasm is extra energy storage.

Two guys can have the same myofibrillar density, but the guy who trains for volume will have more sarcoplasmic growth, looking bigger but having the same strength. So the smaller guys with denser, myofibrillar strength have more functional muscle than the bigger guys with sarcoplasmic growth, right?

Except it's not that simple. The size of a cell cannot increase indefinitely, so the sarcoplasm can't just continue to swell the myofibril until it bursts; so the myofibrils have to grow to some extent to support this increase in sarcoplasm.

So bodybuilders, in actuality, are growing functional muscle when they train. A lot of it is under that “big suit of armor” called sarcoplasm. If that's so, why can't they use it? The answer lies in your nervous system, and the difference in training.

The way that bodybuilders train often calls for isolation work in higher volumes with any number of supplements to boost the results of their training. This works out for them to grow a lot of muscle in a short amount of time.

Those who don't use those supplements, however, often find themselves struggling to get any substantial kind of strength or muscle gain in their workouts. Their functional muscle growth is limited by one MAJOR factor. This is because of hormones.

When bodybuilders use supplements and hormones to boost their training results, they gain muscle with their isolation. Yet, the body isn't catered to release growth hormones or testosterone with isolation movements.

The only way to naturally tax the central nervous system enough to really make those kinds of gains are by training muscle groups and compound movements, with progressively heavier weights.

Isolation training can be supplemental to that, but if you only use isolation training and don't take hormones, you're gonna have a bad time as far as natural muscle strength.

The high volume isolation training will tax energy stores, causing your muscles to recruit more glycogen, but if it doesn't fatigue the muscle itself, as well as the CNS, your myofibrils won't develop to their full potential. So it doesn't contribute nearly as well to functional muscle as compound exercises.

Furthermore, the isolation exercises with a lack of central nervous fatigue leads to horribly undertrained tendons and ligaments. “Oh, with the connective tissue talk again” you say?

Yes, because it is highly important that you train your tendons and ligaments with your compound movements using heavy weights. Partial weight training, weight supports, and isometrics are almost specifically catered to this.

Isolation training plus a high impact sport equals a short lifetime for that athlete, usually because of some ligament related injury (torn ACL, Achilles tendon, etc.)

By training to strengthen those tissues, your spine gets more stability and power, your tendons feel more springy, and your ligaments feel like they could support the Earth itself. Your lifetime as an athlete extends well beyond reason training this way.

This is what separates the men from the boys. Really, getting big muscles isn't impossibly difficult; eat enough protein and a high amount of calories, and train hard on a day to day basis, and you've got some decent gains headed your way. But, if you can't use those muscles functionally, your true strength won't transfer.

Growing big muscles in a short amount of time using isolation movements teaches the muscles to act individually and almost always remain contracted. This way, your body can't function as well as a unit, because you haven't developed your nervous system as much in your training. Also, your muscles can't properly relax, leading to fatigue faster and reduced mobility.

So can you be big and have functional muscle?Absolutely! However, you need to train in compound exercises that teach the body to work as a unit (squats, leg presses, deadlifts, bench presses, etc.) You also need to lift to you maximum so that your central nervous system gets fatigued properly, leading to better overall control of your muscles.

The same applies for connective tissue training, so that you aren't ripping tendons like Dennis Rogers rips phonebooks. You should also learn to relax the muscles, perhaps with muscle control or, often less prestigious in strength training circles, yoga. 

Few people know this better than Bud Jeffries, who made a program specifically for the purpose of big, bulky, or heavy men developing functional muscle. Doing this will grant you much better overall mobility. Of course, you can't outlift gravity, so the heavier you are, the more difficulty you'll have in relation to function strength and bodyweight exercises. But, by following this advice, you'll have a great fighting chance.