Shoulder Impingement: Part 1 – What It Is and Why It’s Important

I recently had the opportunity to speak with one of my professors Mark Butler, a physical therapist I have a lot of respect for.  I asked him what he thought was the most common shoulder problem in the world of fitness.   His response:

Shoulder Impingement

From my own experience and speaking with other crossfit trainers and therapists, the most common problem area for people in crossfit is the shoulder.  Just take a look at the major exercises in crossfit; overhead press, push press, push jerk, pushups, kipping pullups, snatches, dips, muscle-ups and handstand pushups.  All awesome exercises, all tough on the shoulder.  No wonder we have impingement.

Unfortunately, the term shoulder impingement is thrown around quite a bit to describe every type of shoulder pain.  In reality there are several different types of impingement, each with unique aspects.  This is why its important to consult a professional if you are concerned you may have an impingement situation.  The problem can be very complex and impingement can be coupled with other issues as well.

In understanding shoulder impingement first we’ll learn the anatomy.

In this picture we have the shoulder joint.  Here are the key structures:

  1. The humeral head – This is the top portion of the bone in your upper arm.  Normally it should stay snugly fit centered into its socket, the glenoid fossa
  2. Acromion, Coracoid and Coracoacromial ligament – These structures sit above the humeral head and provide a small space aptly named the subacromial space.
  3. Supraspinatus Tendon (part of the rotator cuff), long head of the biceps tendon and a bursa.  These structures sit between the humerus and the structures labeled above in #2 in the subacromial space.  These are the structures that get impinged upon with this syndrome.

In an impingement scenario, the rotator cuff and scapular musculature is not holding the humeral head firmly into the socket.  Commonly the humeral head translates superiorly (goes up) and the contents of the subacromial space gets pinched (impinged) against either the acromion, coracoid or a combination of the two.

This can occur with all different movements of the shoulder.

Dr. Kietrys has an excellent saying about impingement.  He says, “All roads lead to shoulder impingement”   What he meant by this is that most types of shoulder pain end up causing some type of impingement.  So regardless of how you hurt your shoulder (overuse, technical breakdown, overstretch, muscular imbalance, poor posture, dyskinesis) it will most likely end up causing a shoulder impingement.  This is why its so important to avoid situations that may damage the shoulder.  In a lot of cases shoulder pain can lead to a cascade of additional problems.  Now you’ve got a complex rehabilitation situation on your hands or in some cases, surgery.

As discussed earlier, the impingement can be occurring in multiple places:

  1. Coracoid Impingement
  2. Acromial Impingement
  3. Internal Impingement (Thrower’s Impingement)

Impingement by the coracoacromial arch (a fancy term for the acromion, the coracoid and the ligament that connects the two)  is what we discussed earlier.   It’s also commonly referred to as subacromial impingement.  The most important thing to remember about this condition is that the humeral head is not being held tightly into the glenoid fossa (ball into socket) in the correct position during exercise.  This happens for a variety of reasons we’ll discuss in the next articles.  Because of this we get excessive impingement, pain and eventually damage to the structures within the subacromial space.

In subacromial impingement of the shoulder there is typically a painful arc of motion while raising your arms overhead, usually in the 70-120 degree range.

These patients usually have pain when reaching across the body, internal rotation of the shoulder and elevation of the arm into the painful arc of motion as described earlier.  These are a few provocative diagnostic tests to rule in  subacromial impingement syndrome.

Coracoid Impingement – This guy looks especially happy to be having shoulder problems

Hawkins Impingement Test

Internal impingement is a different beast.  This is an impingement common in throwing athletes and occurs with excessive external rotation of the shoulder seen in pitching and in the tennis and volleyball serve.  Although this impingement is specific to overhead throwers, the motion that causes internal impingement is very close to crossfit exercises that require external rotation of the shoulder in an overhead position (kipping pullups, muscle-ups).  Crossfit athletes are also put at risk in other exercises that require a lot of external rotation of the shoulder such as with back squats, the rack position of front squats and the bottom position assumed before overhead pressing with a barbell.  Because of this its important to take precaution to avoid this type of impingement as well.  We’ll discuss prevention strategies later.

Extreme Range of motion?  Yes? Internal Impingement?  Maybe.

Again, please don’t try and diagnose and treat yourself, consult a professional if you’ve got pain.  This isn’t a problem to take lightly.  In the next installments we’ll talk about common causes of impingement and how to specifically prevent these issues in the crossfit population.

Part 2 HERE:

Want to learn more about how to assess your own and your athlete’s shoulder motion during common exercises and find the best exercises to optimize it so you don’t get back in pain again?  Check out Dr. Dave Tilley and my product:

Monkey Method – Movement Essentials

The Ultimate Guide to Understanding and Fixing Technical Flaws in the Handstand, Muscle-up and Olympic Lifts

Here’s to healthy shoulders,

Dan Pope


Behnke, R. S. (2006). Kinetic anatomy. (2 ed., pp. 35-56). Champaigne, IL: Human Kinetics.

Page, P., Frank, C. C., & Lardner, R. (2010). Assessment and treatment of muscle imbalances the janda approach. (pp. 195-207). Champaigne, IL: Human Kinetics.

Wilk, K. E., Reinold, M. M., & Andrews, J. R. (2009). The Athlete’s Shoulder . (2 ed.). Philadelphia, PA: Churchhill Livingstone.

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