T Nation

Upper and Lower Chest?


#1

I had one guy tell me

you can't "work your upper/lower chest". Functionally, your pecs contract as a whole. Anatomically, you have different heads, but it's really just your clavicular head and the pectoralis minor.

Incline/decline just puts different stresses on your shoulder. Incline works the anterior deltoids more, and decline takes the load of your shoulders.

And then some guy told him

You're wrong. The pectoralis major may be one muscle, but any group of fibres attached to a motor neuron can behave independantly of any other group of fibres attached to another motor neuron. While your entire pectoralis major contracts, the extent of which particular parts of the muscle contract can be entirely different. There IS a difference between medial and lateral portions of the pectoralis major along with the clavicular and sternocostal heads.

While you are right that the incline works the anterior deltoids in a higher ratio than the flat bench does, it also works the clavicular head to a higher ratio than the sternocostal head. Decline works the sternocostal head more than the clavicular head.

It's surprisingly common mythos that you can't work "certain parts" of a muscle, it's also bull****.

SOoo whos right?


#2

first guy, heres why :
The pec is one muscle therefor you cant shape it. You should hit it from all angles to build it optimally though. With that said, read this post, its pretty informative. Its from a board member by the name of Belial:

The existence of the so-called "upper", "lower", "inner" and "outer" pectorals along with the assertion that it is possible to isolate one or more of these to the relative exclusion of the others in training, are among the most firmly entrenched myths in Strength Training and Bodybuilding circles. In fact none of these truly exist as either separate and distinct muscles or regions in a functional sense. Even though it could be argued that there appears to be a structural distinction between the upper and lower pectorals (and some anatomy texts do in fact support this distinction though not all do) because the pectoralis-major does originate from both the sternum and the proximal or sternal half of the clavicle along it?s anterior surface (it also has connections to the cartilages of all the true ribs with the frequent exception of the first and seventh, and to the Aponeurosis of the external oblique muscle), this is considered to be a common (though extensive) origin in terms of the mechanical function of the muscle. Thus the pectoralis-major is in fact for all practical purposes one continuous muscle with a common origin and insertion, and functions as a single force-producing unit. The terms upper, lower, inner and outer are imprecise and relevant only in order to make a vague subjective distinction between relative portions of the same muscle for descriptive purposes. They are vague and imprecise terms because there is no clearly delineated or universally defined border between them.
Further it is not physically possible either in theory or practice to contract one region of a single muscle to the exclusion of another region or regions (as a Biomechanics Professor of mine once demonstrated to a bunch of us smart-ass know-it-all?s taking his course, using EMG analysis). When a muscle contracts it does so in a linear fashion by simultaneously reducing the length of its constituent fibers and thus its overall length from origin to insertion. Even where a single muscle is separated into multiple functional units that are clearly defined such as the triceps (which are referred to as ?heads? by Anatomists and Biomechanists), because they share a common point of insertion in order for one head to shorten all must shorten. This only makes sense if you think about it because otherwise there would be ?slack? in one when the other shortened, which as we know does not occur. Note that there are some special cases where one head of a muscle must actually lengthen when the other shortens (e.g. the posterior head of the deltoid in relation to the anterior head during the positive stroke of fly?s), the point however is that even in these special cases there is no ?slack? because there is in fact contractile activity (whether concentric or eccentric) throughout the muscle.

That is not to say however, that all fibers in different areas, or heads are necessarily shortened to the same degree during a particular movement. Depending on the shape of the muscle, the joint geometry involved, and the specific movement being performed, fibers in one area of a muscle or head may be required to shorten more or less than in others (or even to lengthen) in order to complete the required movement. For example during a decline fly though muscle fibers in all regions of the pectoralis-major must shorten as the upper arm is drawn towards the median plane of the body, because of the angle of the arm in relation to the trunk the fibers in what we commonly refer to as the lower pecs will have shortened by a greater percentage of their overall length than those in the upper region of the muscle by the completion of the movement. Conversely when performing an incline fly there is greater shortening in the fibers towards the upper portion of the muscle than in the lower.

Many proponents of the so-called ?isolation? approach to training claim that this proportionally greater shortening of the fibers equates to greater tension in the ?target? region than in others, and therefore stimulates greater adaptation; but this is completely at odds with the cross-bridge model of muscle contraction which clearly shows that as fiber length decreases tension also declines due to increasing overlap and interference in the area of the cross-bridges. Some also contend that the fibers called upon to shorten to a greater degree tend to fatigue faster than others and that therefore there is greater overall fiber recruitment in the region where this occurs, and thus a greater stimulus to growth; but there is no evidence to suggest that a fiber fatigues faster in one position than in another in relation to other fibers in the same muscle. In fact it has been shown that Time Under Tension (TUT) is the determining factor in fatigue and not fiber length. In fact fiber recruitment tends to increase in a very uniform fashion throughout an entire muscle as fatigue sets in.

The ability to ?isolate? a head, or region of a muscle to the exclusion of others by performing a particular movement, or by limiting movement to a particular plane and thus develop it to a greater degree, is a myth created by people who wish to appear more knowledgeable than they are, and has been perpetuated by trade magazines and parroted throughout gyms everywhere. It is pure non-sense and completely ignores the applicable elements of physiology, anatomy, and physics in particular. Quite simply the science does not support it, and in most cases is completely at odds with the idea.
Regardless of the science however, many people will remain firmly convinced that muscle isolation is a reality because they can ?feel? different movements more in one region of a muscle than in others. This I do not dispute, nor does science. There is in fact differentiated neural feedback from motor units depending on the relative length of the component fibers, and this feedback tends to be (or is interpreted by the brain as) more intense when the fibers in question are either shortened (contracted) or lengthened (stretched) in the extreme. However this has to do with proprioception (the ability to sense the orientation and relative position of your body in space by interpreting neural feedback related to muscle fiber length and joint position) and not tension, fatigue, or level of fiber recruitment. Unfortunately it has been seized upon and offered up as ?evidence? by those looking to support their ideas by any means available.

Muscle shape is a function of genetics and degree of overall development. As you develop a muscle towards its potential, it does change in appearance (generally for the better) but always within the parameters defined by its inherent shape. A person who tends to have proportionately more mass towards the upper, lower, inner or outer region of his or her pectoralis-major will always have that tendency, though it may be more or less apparent at various stages in their development, and in most cases appears less pronounced as overall development proceeds. That is not to say that training a muscle group from multiple angles is totally without value. In fact we know that even subtly different movements can elicit varying levels of fiber recruitment within a muscle in an overall sense (i.e. in terms of the percentage of total available fibers) due to differences in joint mechanics, and neural activation patterns, as well as varying involvement of synergistic and antagonistic muscle groups involved. So by all means experiment with different angles in your training, but don?t expect to be able to correct so-called ?unbalanced? muscles this way, or to target specific areas of a particular muscle. Work to develop each of your muscles as completely as possible and shape will take care of itself. If you want to worry about ?shaping? you should pay more attention to the balance between different muscle groups and work to bring up any weak groups you may have in relation to the rest of your physique.


#3

Read through this thread:

http://www.T-Nation.com/readTopic.do?id=1035477&pageNo=1

Should answer most of your questions.


#4

As I understand it, the second guy. The clavicular head and sternal head can be emphasised respectively by changing the exercise. Also, muscles contract from orgin to insertion. The pec has multiple insertions spreading out like a fan down the sternum, but only two origins (only considering the pec major). This is to allow contraction of the pecs with a variety of lines/directions of maximal contraction/strength.

Also my own personal experience is that the upper chest can be trained as distinct from the lower.

Upper & lower = real
Inner & outer = myth (although I strongly suggest you work your pecs both at the point of stretch and the point of peak contraction)


#5

You can work your upper chest more than your lower. This happens for two reasons. One is the sheer area that the pectorals occupy and the other is the presence of the pec minor. There is no such thing as inner or outer pecs. howevcer, any bodybuilder who has lifted and actually made any progress knows that your upper pecs can lag in development if you perform no incline work at all. Mine used to actually be a weak point. Now they stand out fairly evenly.


#6

Inclines work your "upper chest" better by giving it more of a stretch...let me go work on the "peak" of my biceps...


#7

So, this is the practical answer: while you cannot technically isolate different parts of the chest, you should perform incline and decline work as well as flat bench for optimal development. Particularly incline.


#8

All of that is great & an interesting read, but when I started lifting weights I pretty much only did flat bench work for my chest, resulting in my lower chest building up to the point where I could clearly see my insertions along my sternum, except at the top just under my collar bones. I added in incline work and they came up like a charm!

If science does not support it, then I guess science needs to do some more work.


#9

Wasn't there a recent article including mention of "a strap of muscle" running over the chest? In particular, I remember reading the word "gristle". So, where does gristle isolation fit into this? Man, now I need to go get some bbq ribs.


#10

Agree t-ha. i was in the same situation, flat bench for years , upper chest development was poor, added incline bench and DB's, and my upper chest grew fast,i really dont care what science says sometimes, if i didnt do inclines my upper chest would still of sucked.


#11

absolutely. i don't do any incline work and my upper chest is lagging. ah well, i can always catch up quickly with a little incline work.