T Nation

Shaping: Can you target specific portions of a muscle?


#1

What are your thoughts on the debate over whether a certain portion of a muscle can undergo hypertrophy from a particular range of motion?

For example, does doing Incline BBL Bench Press work the upper portion of your pectoral more than, say, Flat bench?

I'm starting to question the science behind the assertion that you can't shape a muscle. After I stopped doing incline presses (for a couple years) I seem to be lacking development in the upper pectoral region - but the lower and outside edges are growing nicely.

So is a muscle shaped purely through genetics or is there a training component as well?


#2

Incline presses DO target mainly the clavicular head of the pectoral major - or the upper chest. You can usually see this upper half very VERY defined in a bodybuilder.

You CAN emphasize a specific head of the pectorals, but I'm not sure as to wether you can emphasize muscle fibers of the inner part of that head, as opposed to hitting the WHOLE head.


#3

Different motions require recruitment of different muscle fibers. Therefore, the muscle fibers that will be forced to contract maximally, and undergo the most damage (consequently undergo the most repair and resultant hypertrophy and shape) will be those fibers. Therefore, training different angles, or portions of the full ROM will alter muscle fiber recruitment, and thereby alter regions undergoing hypertrophy and consequently muscle shape.

That said, it is generally impossible to prevent some muscle fibers from firing...for example, you can't just contract the long head of your brachiallis, without contracting the short head. But by changing angles of your hands and wrists, also tempo (since some fibres are slow twitch), you will recruit different regions of the muslce and can its shape.

Good Luck


#4

No, you cannot shape a muscle. Your muscle shape is pre- determined by your genetics.


#5

Thanks guys, exactly what I needed to hear. Back to Incline.


#6

you can't shape muscles it's determined by tendon insertion. However, you can stress more of one muscle than another, but changing exercise or hand position, which will make the appearance of shaping the muscle.Example, working different types of curls can stress on side of the biceps brachii or the other, and you can give the illusion of peak by doing this, as in extreme supinated DB curls, conentration curls, etc


#7

You can increase or decrease the size of a muscle at a certain angle, but you can't add peaks, striations, or cuts.

So it is possible to make the upper portion of the chest larger than the lower portoin, but not possible to add more striations to it.

I think the term "shape" needs to be redefined for clarity's sakes.


#8

Your pecs aren't just one muscle. There's the clavicular and sternal heads along with the pectoralis minor too. Each bundle wrapped in it's fascia works as a unit and it's shape is based on genetics. You can work one bunch or another by changing the angle of the motion of the joint those particular muscles move. The overall shape of the area is going to change as the relative sizes of the various heads change.

So if you do flat and decline bench the top area of your pecs isn't getting much stimulation and the "shelf" where the edge of the muscle blends in at the clavical will go away and the upper pec looks less full.

I used to do flat and incline, then switch to decline and incline. Now I do flat medium grip bench and wide grip high neck bench. It does alter the shape some.


#9

i was a trainer for a really shitty company for awhile [ i'm not naming, we'll just call it 24hr. fitness]and to train there you had to get the "24-5" certificate. the "course" was tought buy apex nutrition, which is to 24 as biotest is to t-mag. there were 2 instructors, and one of them was trying to convince a class about 40 deep that hand placement and variations on a theme didn't hit the muscle any differently, and in the same argument told us that close grip benches emphasize the triceps more. after pointing out his contradicting statements and having a good 5 min arguement with this clown that hand placement and different excersises do have a targeted effect on the muscle [in class] the district manager pulled me aside and said if i keep causing trouble i might as well find a new job. it's pretty simple man, when you incline do you feel it more in the upper chest? if so, then you know where it's workin. to clarify, one of the instructors did know what he was talking about, but it wasn't the ass i was arguing with. oh, and i left the company based on their total lack of integrity and morals.
yall be good, flash


#10

"for example, you can't just contract the long head of your brachiallis, without contracting the short head."

I believe you mean the biceps brachii, as the brachialis has only one head.


#11

"Anatomy Eric" strikes again!!!


#12

All this talk about upper chest and so on has got me thinking that maybe there's some confusion about what "shaping" means.

If you do incline work (low incline, that is), then you're going to hit the clavicular (upper) pec muscle. This will then hypertrophy, bringing it out. If you do flat work, then you hit the sternal pec, and that lower muscle will hypertrohpy. Thus, you get the illusion of "shaping the pecs" because there are actually two different muscles that are generally (incorrectly) viewed as one.

But if you try to "shape" the lower pec or the upper pec in isolation, that's not going to happen. You can make either one larger or smaller; changing either one's shape isn't possible. And by the same token, you can do all the preacher curls you want for your biceps, they aren't going to lengthen more than they already are, and you aren't going to get a better peak if you do concentration curls for them, and so on.

So for most muscles, the idea that you can shape them is wrong.