What effects the shape of muscles?

orbot · October 26th, 2009, 11:51 AM

Here's something I've been curiousg about, bear with me if it is a stupid question. It's about the shape of muscles - let's take biceps as an example:

Some people's biceps seem to peak and get very "sharp" when they strain the muscle. Some remain "bulge-shaped" like that even when the arm is fully extended, while others have more "loaf-shaped" biceps that are evenly thick from the upper end of the muscle all the way down to the bend of the arm.

Does this have anything to do with genetics?

Does this have to do with exercise type (resistance vs. reps, ROM, etc.)?

Does this have anything to do with post-exercise stretching of the muscle?

Do other factors play in, such as body fat, supporting muscles, etc.?

In case genes has nothing to do with it, I suppose you can train your muscles to be shaped in whatever way you prefer - but from a pure muscle power standpoint: Is the "bun" or the "loaf" shape more desirable than the other or is the shape of no importance in that matter?

**IMFREAKZILLA** · October 26th, 2009, 12:04 PM

heavy weight,light weight,form ,reps and routine and genetics

orbot · October 26th, 2009, 12:16 PM

Thanks for the super-quick answer, but how exactly do these factors play in to the shape of the muscle?

For example, the form. I would assume that a short ROM gives you a "bun" muscle, whereas a full ROM gives you a "loaf" muscle (wow, this terminology - what am I, a baker?). Am I right in my assumption?

Do heavy weights and few reps give you "bun" muscles while light weights and more reps give you "loaf" muscles, or is it the other way around?

And what did you mean by "routine" in your post? What aspects of the training does that term represent, since you mentioned "weight", "form" and "reps" separately?

**tooncesthecat** · October 26th, 2009, 12:28 PM

Genetics would account for ~ 95% IMO. This is most clearly observed with pro bodybuilders. Some have remarkable biceps or calves or some other muscle group. For the most part, they all train to be the best they can be but genetics will dictate shape and to some degree size of the muscles. The 5% that can be varied will reach max potential with exercise variation to ensure a muscle is worked in varying movements.

As to whether one shape is more desirable than another, that would depend on what your goals are.

orbot · October 26th, 2009, 01:37 PM

Thanks for the answer, tooncesthecat. I find all of this very interesting.

So whether one shape is more desirable than the other would depend on my goals? I suppose you mean whether I primarily want explosive power, raw strength, stamina, or something else?

I don't know what my ultimate goals are in terms of muscle shape - although I know what shape I would prefer from a pure aesthetic standpoint in case the difference in muscle function is negligible.

However, should the difference in muscle function not be negligible, my goals may very well depend on what functional advantages any of the two shapes would have over the other.

...so, let me shoot that as a question right back at ya: In what ways is a "bun" muscle more useful than a "loaf" muscle, and vice versa?

**tooncesthecat** · October 26th, 2009, 02:05 PM

Not really more useful, but some bodybuilders like the peak of a "bun" biceps vs a "loaf" but either way i would just train your ass off and be happy with your genetics!

**IMFREAKZILLA** · October 26th, 2009, 03:13 PM

if you are using too heavy weight for an exercise you start working the wrong muscle
group and they come into play ,lighter weight and proper form will get you a more sculpered
physique if thats what you are looking for.

**pliny_2001** · October 26th, 2009, 11:35 PM

Muscle shape is going to be determined by the oft-referred to but rarely defined "muscle belly." It's like this: tendons hold your muscle to the bone. The genetically pre-determined arrangement of fibers in the muscle tissue, and then the ratios in length between the muscle and its attaching ligaments speak to what shape your muscles are going to have. You can make them bigger, but they're going to grow in the same general shape as this pre-determination.

At the borders, there probably is some give: Arnold talked about being able to work on peaking his biceps, and selected exercises accordingly (though his biceps had a strong peak from the very beginning). Science is against Arnold here, but I wouldn't bet against him - but in general, there's not much you're going to do about shape.

One's not more useful than the other. There's isn't a difference in athletic performance due to muscle shape. And within very small margins (toonces' 95+% probably isn't inaccurate), there's not much to do with shaping (other than size and bodyfat).

orbot · October 27th, 2009, 09:47 AM

Wow, thanks for all the answers.

One could say that body building is like uncovering your own physique, and discover your own personal statue of David inside the marble block. This will be really exciting, seeing what genetics I have inherited and how my muscles have been destined to look since the day I was born!

I'll heed toonces' tips; train my ass off and be happy with my genetics!