What Muscle Is Most Limited By Genetics?

Perhaps the question ought to be:

Which one isn’t?

You’ve heard it all before; it is dependant on your genes…the proteins and other assorted growth factors that these genes express.

So we take our shotgun, point it at the target of muscle groups and pull the trigger, hitting which target? All of them.

The concept of Anatomical Variation is what you really want to know about. AV is a highly influential factor dictating the shape, symmetrical & size characteristics, even whether or not a muscle is existent in the anatomical inventory of your body.

Let’s take as a small example, the palmaris longus. In 86% of the population, it exists as a tiny muscle on the underside of the lower forearm, proximal to the wrist. The unlucky minority of the rest of us (myself included) lack it. Oh, well I guess that we don’t need it, anyway.

But gee, it sure does looks good.

Palmaris Longus:

No Palmaris Longus ☹️:

Another example is the pyramidalis, two lovely little triangular-shaped muscles in the lower abdomen located bilaterally on either side of the linea alba.

Tragically, 20% of us don’t have them.

Some people sport only 6-packs, others have 8.

These are only two simple examples of muscles limited to non-existence by things genetic. Missing muscle groups are not that uncommon and you can’t build what’s not there.

As far as bodybuilders are concerned, genetically limited muscle growth and absent muscles are the cruelest punishment for Original Sin that Great-Anatomist-In-The-Skycould dish out to us.


Now, on the other hand, there are cases, mind you exceedingly rare, that consist of a single nucleotide polymorphism (SNP) affecting the MSTN gene. This modification results in the absence of myostatin.

Myostatin is a protein that is primarily responsible for limiting muscle growth. Individuals with this genetic mutation have few limitations or restrictions on muscle growth.


So, you might ask yourself, why would Mother Nature be so cruel as to sentence me to a life not humongous? Why must I be stopped from kicking sand in weaklings’ faces and stealing all their girls? What did I ever do to Her to deserve this?

Yes, you are guilty, guilty as sin. You were born without this mutation, just like 99.99% of the world population.

She actually has an excellent excuse to limit your muscle growth. To allow unlimited muscular growth, the individual would pay a high physiological cost and would most likely suffer a shorter life span (reasons which have enough meat on them to be well worth the topic of another long post).


The absence of this governing factor (Myostatin) results in a proportionally larger number of fast-twitch muscle fibers and double-musculature. This blessed occurrence of genetic divinity, as far as bodybuilders are concerned, is the musclehead’s equivalent of The Holy Grail or The Lord’s Provision of Manna (Exodus 16:14).

Take a look at the guy in this photo below:

Behold here what the power of a single genetic mutation has wrought!

Consider this colossal beast for a moment:

he is like an impossible, heavily muscled prehistoric bison of genuinely epic proportions.

His startling size, this incredible quantity of muscle, has been created without so much as a single bench press, deadlift or squat!

Think of it. All that beef…and this immense creature didn’t even have to break a sweat for it!?

I am astonished, aren’t you?

He is a fortunate guy.

Well, at least until the local butcher shows up looking for some Prime Cut.

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