Skip to content
Home » Debunking Inner Chest Exercises: Why You Can’t Isolate Your Pecs

Debunking Inner Chest Exercises: Why You Can’t Isolate Your Pecs

If you’re someone looking to build a more defined chest, or you’re unhappy with the development of your pecs, chances are you’ve Googled the terms “inner chest exercises” or “inner chest workout”.

Well, you’re in good company. A quick Google search reviews 58 million results on the topic, including well-regarded sources like Men’s Health, Onnit, and ATHLEAN-X that many turn to for fitness knowledge. Everyone wants an impressive inner chest and they know that.

These terms refer to exercises that supposedly target the inner portion of the pectoral muscles, resulting in a more chiseled chest.

However, the question remains: do these exercises actually work?

Anatomically, the pectoral muscles connect from the sternum to the humerus, and when exercised, the entire muscle stretches and contracts. As a muscle does.

There is no way to workout the inner chest, unfortunately. Despite this, the idea of inner chest exercises has persisted in the fitness community, with many trainers, magazines, and internet personalities advocating for specific exercises to target this area.

In this post, we’ll take a closer look at the concept of inner chest exercises and explore the scientific evidence behind them. We’ll delve into the anatomy of the pectoral muscles and explain why targeting the “inner chest” is not possible.

And we’ll explore how do you actually make your inner chest more defined and give your pecs that shelf look.

So, let’s get started and uncover the truth about inner chest exercises.

Anatomy and Function of the Chest Muscles

It’s quite ironic that the websites promoting inner chest exercises make claims such as “contrary to popular belief, you can target the inner chest” or “it’s a common misconception that you can’t isolate the inner chest”.

Well, good thing that at TheBodybuildingBlog we use science to back up our claims. And debunking fitness myths is what we do.

The pectoralis major, what we know as the chest, is a large fan-shaped muscle that stretches horizontally from the middle of the sternum to the humerus bone in the arm (source). It is comprised of two distinct muscle heads: the clavicular head (upper chest) and sternal head (lower chest)(source).

inner chest exercises anatomy of the chest

The primary function of the chest muscles is to bring your arm towards the center of your body.

While the upper chest also assists with lifting the arm upwards. This is why exercises that target the upper chest often involve some form of incline (such as an incline bench).

As you move your arm inward, the muscle contracts, and when you release it back out, it stretches.

As you can probably notice, there is no “inner chest” region. There’s no need for fancy grips or modifications to target specific areas. The only exception is using a slight incline (around 30 degrees) to better engage the upper chest.

Why Inner Chest Exercises Do Not Work

We are going to use the bicep as an example.

Saying that you can target the inner chest is the same as saying that you can target the bottom part of the biceps where it connects to the radius (forearms).


Doesn’t quite make sense, does it?

You cannot isolate the inner or outer chest with specific exercises as the entire chest muscle is engaged during any chest exercise.

Common Misconceptions of Inner Chest Exercises

The most common example by those who believe in inner chest isolation is pulling your arm across your torso, past the center, you can feel and see the inner chest contracting.

The truth of the matter is that what you are doing is you are shortening the lower chest muscle to it’s maximum capacity.

A really good comparison is your chest when you’re doing barbell bench press and when you are doing dumbbell bench press.

With the barbell, your range of motion is quite limited range of motion, as you cannot bring your arms much closer than shoulder width, dumbbells allow you to contract the chest muscle much more by bringing your arms closer to each other.

However, this does not necessarily target the inner chest more, it just means that you’re shortening the muscle more.

Non-Spanning Muscle Fibres

I have seen non spanning muscle fibres being brought up by people such as ATHLEAN-X. These are muscle fibres that don’t connect from tendon to tendon. Rather, they attach to the tendons indirectly thorugh a myotendinous junction (source).

The idea is that by contracting the chest muscle to its maximum, you are enforcing these non-spanning muscle fibres, which are sitting around your inner chest.

While non-spanning muscle fibres do exist, this is a stretch. No pun intended.

Even if you were to engage these muscle fibres they make up such a small portion of the total muscle mass that any changes will go unnoticed. Not to mention that they are spread around the chest muscle, they’re not all concentrated at the inner chest.

And lastly, there is literally zero scientific evidence to support this claim. Except for this 1999 study that briefly mentiones non-spanning muscle fibers in rats.

Hey Jeff Cavaliere, you dropped this:

inner chest exercises myth

The Problem with Inner Chest Exercises

There are two main problems with inner chest exercises:

  1. Overcomplication; and
  2. Waste of time and energy

There is one incredibly common trend in the fitness community and that is to overcomplicate everything. Working out is simple. Not easy, but simple.

You exercise a certain amount of times a week, keep proper form, add progressive overload, and rest.

Adding all of these variables only serves to discourage and overwhelm beginners and intermediaries, preventing them from starting or sticking to their workout routine.

And, let’s be honest, they’re a waste of time and energy.

Instead of you doing an extra few sets of a press variation or dips, you’re wasting your time doing “3D crossover”.

Great name Jeff. Very original.

How To Develop The Inner Chest

While you cannot specifically target the inner chest with exercises, there are ways to make it more prominent.

Two things that can help are:

So what is actually going to help you bring out the inner chest? Two things:

  1. Lower body fat percentage
  2. Increasing overall size of the chest

Lower body fat percentage

Excess fat on the chest can lead to a smooth appearance and hide the inner chest line, even if the muscles are large.

This is true for all major muscles. The lower your body fat percentage, the more noticeable and defined your muscles will appear, and the inner chest is no exception.

Funnily, the myth surrounding the inner chest is similar to the age-old six-pack abs myth surrounding. You know, the same way magazines and influencers swore that by exercising the abs you’re going to get a six pack.

Now, if you were to ask anyone at the gym, they’ll tell you that if you want get six pack abs, you will need to drop some extra body fat percentages. And at least you can exercise the abs, unlike the inner chest.

I hope that one day we’re all going to look back at these inner chest exercises and laugh.

Increasing Overall Chest Size

To develop a prominent inner chest, it’s important to focus on building the entire chest.

Think of it like a canyon: when the mountains are big, the canyon appears deeper.

Similarly, when the chest is well-developed, the inner chest will be more defined. Stick to basic exercises like bench presses, dumbbell flys, and dips, and focus on getting stronger with those.

You don’t need to do every exercise, just choose the ones that work best for you and progressively increase the weight.


In conclusion, the idea of targeting the inner chest through specific exercises is a misconception.

The chest muscles, including the pectoralis major, cannot be isolated or targeted in a specific region.

Despite the fitness community promoting “inner chest exercises,” the entire muscle stretches and contracts during chest exercises. The best approach to achieve a more defined inner chest is to increase the overall size of the pecs and reduce your body fat percentage.

Rather than wasting time on futile attempts to target the inner chest, focus on progressive overload and proper form to make progress. It’s time to stop overcomplicating the workout routine and focus on the basics.

Join our mailing list!

* indicates required

Leave a Reply