build inner chest

Building up the inner portion of your chest is an important step in achieving well-rounded development that really gives your pecs that thick, defined and “separated” look.

But what is the most effective way to specifically target this area?

What are the very best inner chest exercises, workouts and form tips to gain inner pec muscle with maximum efficiency?

Run a search online and you’ll find an endless number of different articles and videos outlining various chest pressing and  variations to supposedly “isolate” the inner fibers of the pecs for greater size gains…

However, if you take a look at the anatomy of the pectoral muscle and the way in which the fibers run, you’ll see that it’s actually not possible to specifically isolate the inner chest without also hitting the middle and outer fibers with the same amount of overall stimulation.

The pec major is basically made up of 2 sets of fibers: the upper clavicular fibers and the lower sternocostal fibers.

pec anatomy

The clavicular fibers originate on the collarbone and insert onto the humerus (this portion is typically referred to as the “upper chest”), while the sternocostal fibers originate on the sternum and insert onto the humerus (this portion is typically referred as the “lower chest”).

Because each of these sets of fibers have their own unique origin/insertion points and separate nerve innervations, it IS possible to specifically target the upper and lower chest by utilizing different pressing and flye angles. Incline movements will shift the emphasis onto the upper clavicular fibers, while flat and decline movements will specifically hit the lower sternocostal fibers.

In terms of targeting specific areas of the chest for increases in size, however, this is really all that you have control over.

You can’t isolate or shift more emphasis onto the “inner chest” for the simple reason that there really is no such thing. This is because when one strand of fibers contract along the pec muscle, the entire fiber as a whole contracts.

muscle contraction

It doesn’t matter what specific exercises, angles or training techniques you use; if you want to stimulate the “inner pecs”, then the “middle” and “outer” portion of those fibers must also fire as well.

This doesn’t mean that you can’t build inner chest muscle, it just means that you can’t specifically target this area of the pecs at the exclusion of other areas.

In other words, in order to build inner pec mass, you simply have to focus on building your entire chest as a whole. As your chest gets bigger and stronger over time, your inner pecs will also grow along with it.

But trying to employ so-called “advanced” techniques to somehow get a better “squeeze” on your inner chest and gain more size specifically in this area is really just a waste of effort, and may even have potentially negative effects if it distracts you from the basic, proven chest exercises that pack on overall size in the most efficient way.

The only possible factor to take into account here is that, since the lower sternocostal fibers attach onto the sternum, building up these fibers will likely have a more noticeable impact on your inner chest gains. For that reason, the best inner chest exercises would technically be any type of press or flye performed at a flat or decline angle.

However, this is basically a redundant point, since the sternocostal fibers make up the vast majority of your total pec mass anyway and should be treated as the focal point of your chest training routine regardless.

Best Inner Chest Exercises: The Bottom Line

inner pec muscle

So what’s the bottom line here?

Stop worrying about your “inner” or “outer” chest and just focus on maximizing your overall chest gains as a whole through proper exercise selection, form and progressive overload.

If you want to learn how to add size and thickness to your entire chest in the most effective way, make sure to check my recommend sequence of the 3 best chest exercises as well as these 4 chest training tips to help you see the fastest gains possible.

If you found these tips helpful, make sure to get your personalized training, nutrition and supplement plans using my free interactive video presentation below…

  • I found this article very interesting. Learning about how the chest is put together makes it easier for me to plan my workout. I have a problem isolating the lower chest muscles when I lift. I never feel the burn. I do decline press mostly and am adding flye. What is a good way to make sure that I the muscles in my lower chest to work as hard as the ones in my upper chest?

    • Sean Nalewanyj

      The best way to hit the lower chest is using decline movements. Decline dumbbell press, standing cable flys (pulling from high to low) and decline flys (place a decline bench between a cable stand) will be your top exercises.