T Nation

Changing Muscle Shape

I am wondering if it is possible to change the shape of any particular muscle. Someone wrote this about it on a site online and I wonder what you all think:

"Actually, your “chest” muscle is comprised of two main muscles: the pectoralis major and pectoralis minor.

Your pectoralis major is the “bulk” of the muscle, and spreads from your sternum to your shoulder. This is the muscle that you see.

Your pectoralis minor is actually beneath the major muscle, and serves mainly as a “tie in” to the shoulder joint.

It is a myth that you can work “upper” or “lower” pec muscles. This has been confirmed time and time again - even through electrodes. When you shift the workload, i.e. by performing an incline or a decline, you simly change the way various muscles interact. For example, an incline bench press incorporates your deltoids (shoulder muscles) to a greater extent, while a decline bench press requires more involvement from your lats to maintain the angle of your arm.

No matter what “angle” you hit the pecs from, the entire muscle can either contract, or not contract. The muscle is comprised of motor units, and a single motor unit is a group of neurons/nerves in the muscle. Motor units are NOT localized - one motor unit is typically spread evenly throughout the muscle. So whether you perform an incline or decline, the muscle is still only going to contract or not, it doesn’t contract in a specific “area”.

Flyes perform the main function of your chest, namely moving the upper arm closer to your mid section. A bench press, on the other hand, mimics this movement but also changes your elbow angle, therefore involving the triceps and shoulder to a larger extent than fyes.

In short, there is no such thing as “inner pecs” or “lower pecs”.

This doesn’t mean that you shouldn’t use a variety of angles - by changing from incline to decline, etc, you work different groups of muscles and force your central nervous system to continuously change its mode of adapation, and this is one of the stimuli for hypertrophy (muscle growth).

However, you are stuck with the current shape of your pectoralis muscle. You can make it larger or smaller, but short of tearing or otherwise physically manipulating it, you cannot change it’s shape.

Having said that, many people who feel their “inner” or “lower” pectoralis muscles aren’t developed, simply have too high body fat. , revealing the muscle definition. "

What do you think???

correct, w/some minor diff for certain muscles, tricep shape MAY see minor change in shape over a LIFETIME if for example one twin did only frenchpresses and the other does only pushdowns (the french press guys arms will be ALOT larger also) delts can see a diff also if only front or only side raises are used, and the back is made up of so many muscles that if you only did rowing movements or only did chinning movements you could see a difference, but in general no you can not shape a muscle. peace

The short answer is:False!
You can shift emphasis between upper and lower pecs.Read “made to order muscle” in the T-mag archives.

It has been suggested that it is possible to change a muscle shape owing to the fact that a muscle is made up of fast and slow twitch fibers. The fibers apparently are not evenly distributed throughout the muscle, so therefore one can conceivably preferentially develope one of the fibers. How one would figure out the distribution so that the knowledge can be exploited is a difficult question to answer.

So the answer is…yes or no?

i don’t really know what the answer is, but a little common sense and application of basic engineering principals suggests that it is possible to shift the stress area within a particular muscle. think of a muscle as being a hankerchief with three corners pinned in place. the force produced by pulling on the loose corner results in a reactionary force that is equal to the applied force but not equally distributed throughout the entire hankerchief. it is unevenly distributed throughtout the entire network of fibers. if you pull it hard enough to make it tear every fiber won’t tear by the same amount will it? no, it will tear closer to the point of force application which happens to also be the area of highest stress. i would imagine that muscular microtrauma tears are similar in this regard, so if you change the angle and thus the point of stress application you will cause localized microtraumas and greater muscular growth in theses higher stress areas. no?

Can I get some more feedback here please?

(Taken from an old M.M 2000 piece, but still valid!)

14 – You can completely reshape a muscle by doing isolation exercises.

You can’t limit growth to only one area of a muscle. Larry Scott, for whom the
‘biceps peaking’ Scott curl was named, had tremendous biceps, but he didn’t
have much of a peak. The shape of your biceps, or for that matter, any muscle,
is determined by your genetic makeup. When you work a muscle, any muscle, it
works on the all-or-nothing principle, meaning that each muscle fiber recruited
to do a lift – along the entire length of that muscle – is contracted fully. Why
would a certain number of them, like the ones in the middle of the biceps,
suddenly start to grow differently or at a faster rate than its partners? If
anything, the muscles that are closest to the insertion points are the most
prone to mechanical stress, and you don’t see them get any bigger than the
rest of the muscle. If they did, everyone would have proportions like Popeye.

This is true of any muscle, but you’re probably thinking, what about quads? I
know that when I do hack squats with my feet together, it tends to give me
more sweep in my legs. Sure it does, but the quadriceps are made up of four
different main muscles, and doing hacks with your feet together forces the
vastus lateralis muscles on the outside of the leg to work harder; consequently,
they grow proportionately along their entire length and give the outer quads
more sweep.

As further evidence, take a look at a picture of any young professional
bodybuilder before he was developed enough to become a pro. He will have
virtually the same structural lines as he does today. All that has changed is
that his muscles are now bigger…Was this what you were looking for
rudedawg?..(Joey Z.)

There are some hings I take exception to. First, Pect Major and pect minor aren’t your two chect muscles. Pec major is divided into Pec Major Clavicualr and Pec Major Sternal. Both these muscles act at the shoulder joint and are responsible for Bench pressing and Flies, etc. Pectoralis Minor is a SHOULDER GIRDLE MUSCLE and is responsible for scapular protraction and medial rotation. It has little to do with the chest muscles we see on a BB and little to do with the exercises mentioned. So that’s incorrect.

Second I disagree with the quaote and agree with hetyey225 and others about changing shape.

Third, I disagree with the notion that you can't train upper chest and lower chest separately. Pec Clavicular (upper chest) is a prime mover in flexion of the shoulder (same as front raises) and Pec strnal is a prime mover in extension (same motion as in a dumbell pullover). So to train one separate of the other, these opposite movements can be used. Understand that they aren't hardcore chest movements but I'm talking Kiniesiology here. It works though. Try this: This is done with a straight arm. 1)Place your arm under a table 2)Place he opposite hand across your pec running up toward your collar bone. 3)Try and lift the table up. (provided the table is heavy enough to resist your arm) 4)You should feel your upper pec fire. 5)Place your hand on top of the table 6)Press down 7)You should feel your lower pec fire

Point made…Hopefully. Great post, Peace.

I think the short answer is no. Even if muscle shape change is possible, it is not something that you can directly control to desirable effects.

Thanks for the input and in depth answers… great debate subject I guess, since there are different philosophies supporting both sides. I will keep looking for any info on this subject and if anyone else has any more to add I appreciate it.