The Serratus Muscle: Why It Matters



The serratus muscle, or more appropriately the serratus anterior, is one of the most under appreciated and under trained muscles in the human body.  Although the serratus muscle is only a stabilizer for other muscles, it is still vital to your success in overhead motions and upper body pressing motions. 

Every time I hear a lifter telling me that his/her shoulder is in pain from overhead presses, the first muscle I think of is the serratus muscle.  Unfortunately, pointing fingers and wearing your pride on your sleeve will not properly educate people on how to build up this muscle group and understand it’s function and purpose.  In this post, we are going to go over this elusive muscle group and reveal how the serratus muscle may be the key to help you build a killer upper body. 


Origin And Function Of The Serratus Muscle

The serratus muscle is visible, if you are lean enough, just underneath your armpits in front of the wings of your lats.  Serratus is a Greek word which means “sawtooth”.  Therefore you should be looking for a muscle under your armpit that looks like a sawtooth. 

It originates on the ribcage anywhere from the first to the ninth rib and it inserts on the medial border of the scapulae near the thoracic spine.  This muscle covers a huge amount of space. 

The function of this muscle is to protract the scapulae during pressing motions and also to elevate and upwardly rotate the scapulae during overhead motions.  Another function of the serratus muscle is to keep the scapulae against the rib cage during protraction.  This will be important later.


How The Serratus Muscle Leads To Dysfunction

If the serratus muscle is weak, then the shoulder complex becomes unstable.  Any sort of upper body exercise can subject a lifter to shoulder problems.  One common problem from a weak serratus is shoulder impingement syndrome

Shoulder impingement syndrome typically happens when the tendon for the supraspinatus muscle gets physically pinched by the humeral head against the acromion process during pressing motions. 

Another common issue from a weak serratus is a winged scapulae.  If you examine somebody without their shirt on and see the medial border of the scapulae protruding out against the skin, then they have a winged scapulae.  Any sort of pressing motion and/or overhead motion will display instability and/or discomfort. 

When looking at the shoulder during normal circumstances, it should be centered directly in the middle of the glenohumeral socket.  If, however, there is an imbalance caused by a weak serratus muscle, then the scapulae will become unstable, which will then cause the humeral head to become unstable as well.  This can cause the head to glide either too far forward or too far backwards. 

Typically, most lifters do too much pressing and too little pulling to balance the shoulder.  When this happens, the muscles on the anterior side (front) of the body become too strong for the muscles on the posterior side (back) of the body.  The shoulder caught in a war between both of these sides ends up getting pulled forward.  This is called anterior humeral glide


Strengthening The Serratus Muscle

One thing I can say in complete confidence is that none of the shoulder problems in the above section are mutually exclusive, they are all interrelated.  Now I am not saying that just by strengthening the serratus muscle you will be cured from all of these movement disorders.  That is just absolutely false.  There is more to fix with those disorders, however, fixing the serratus is definitely a huge step in the right direction. 

To strengthen the serratus we want to do two simple exercises:

  • Wall Slides
  • Prone Thoracic Extension


Wall Slides

The wall slide is incredible in that it is so simple and yet so unbelievably effective.  It literally saved my shoulders when I had a winged scapulae.  What makes the exercise even better is that it can be done anywhere, so long as there is a wall.

Stand about a foot length away from a wall and place both of your arms on the wall about shoulder width apart.  Begin to slowly slide your arms straight up the wall to full lockout.  As your sliding your arms up the wall try as hard as you can to keep your shoulder centered in the socket.

If you recall earlier in our discussion about the function of the serratus muscle, I stated one of the functions of the serratus is to wrap the scapulae around the rib cage during overhead motions.  People with a winged scapulae, or impingement, have lost this ability in one or more of their scapulae. 

Luckily, the wall slide addresses this problem.  When performing the wall slide, simply press your elbows into the wall with a moderate amount of force while sliding your arms up the wall.  This will force the serratus to contract and wrap the scapulae around the rib cage. 

Start out performing sets of 20 repetitions for 2-3 sets every single day you are in the gym.  When that gets too easy, move your elbows inside your shoulders, giving you a narrower grip.  This will challenge the serratus more and will provide better rehab for your shoulder. 


Prone Thoracic Extension

The prone thoracic extension hits the serratus muscle from a different position than the wall slide.  Although this exercises looks even more simple than the wall slide it is still very effective. 

Often times when performing overhead exercises, such as the press, lifters tend to hyperextend the mid-back in order to lift more weight.  Although this may benefit your press in the short term, your shoulders will pay a price in the long term. 

The prone thoracic extension, teaches you how to activate the serratus muscle AND maintain a proper spinal position at the same time. 

As the title suggests, this exercise is performed in the prone position (face down) on either a table or the floor.  The arms are then placed to your sides with the elbow pits forming a 45 degree angle, similar to the bench press. 

From here, drive your elbows into the ground as hard as you can and try to imagine wrapping your scapulae around your ribcage as you are doing so.  Also imagine screwing your shoulders into external rotation while pushing down. 

The point of this exercise is to force proper spinal position while enforcing proper scapular mechanics.  This is more of a test of endurance (both mental and physical) rather than strength, therefore, this exercise should be held for at least 5 minutes. 



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