[Muscle Monday] 5 Reasons Why You Should Respect the Pect(oralis) Major

The next few episodes of Muscle Monday will be dedicated to discussing important muscles related to Posture.  Questions about posture are probably one of the top things people ask me about on a regular basis, and the answer is not as simple as it seems.  Posture involves many components which need to work together just-so in order to create the ideal scenario for your body to function at its best.  

Today, we will be talking about the might Pectoralis Major.

Photo Credit: Kenhub.com

To say that this muscle is important would be redundant, because (almost) ALL muscles have a specific function, but this one in particular often gets a bad rep because it is associated with poor posture.  In reality, it is an extremely versatile muscle that is used in most shoulder movements.

Let's explore some fun facts about this muscle

Fact #1:  The pec major has two portions:

• Clavicular Fibers (purple):  attach from the collar bone (clavicle) into the humerus
• Sternal Fibers (green):  attach from the sternum (center of your chest) into the humerus. 

Fact #2:  The pec major can affect both the glenohumeral (shoulder) joint and the the scapula
Due to its attachment on the clavicle, when the two portions of the pec major work together, they can depress​ the shoulder girdle

Fact #3:  The pec major performs movements in 5 planes of shoulder motion
Because the muscle has two portions, the orientation of the muscle fibers allow it to move your shoulder in several planes of motion.  The clavicular fibers assist with shoulder flexion while the sternal fibers assist with shoulder abduction AND extension.

When the two portions work together, they will perform shoulder horizontal adduction, as well as shoulder (glenohumeral joint) internal rotation.

Fact #4:  Constantly sitting in a "slouched posture" will result in your pec major to get tight

Because it is not just due to one factor, having "bad" or "slouched" postures have a number of consequences. By slouching forward, your shoulders tend to rotate inwards, resulting in the pec major being put on slack. Over time, unless consistently stretched in the opposite direction, your body will adapt to this position, resulting in increased tension contributed by this muscle, which perpetuates the "rounded shoulders" position.

Fact #5: In order to adequately take care of your body, you must do a combination of strengthening and stretching.

It's all about balance.  First of all, try and think about what positions you are in the most frequently and take the time to stretch in the opposite directions, no matter what that may be.  Because most of us these days spend a lot of time sitting in front of a computer, on the couch or looking at our phones (or a combination of all 3?), you must make an effort to make sure that the muscle doesn't get too tight.  Conversely, if you perform a task that requires a lot of pec use - such as playing a bowed instrument (Right arm), playing tennis, etc., you may want to invest a portion of your exercise routine to working on building strength, as it is also a key player in your overall shoulder stability.  

Take some time and check out this stretch to help improve your shoulder's powerhouse.

Next week, we will be discussing the Pec Major's little brother, the Pec Minor.  You're not going to want to miss it.

​Until next time, stay happy and healthy!