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Shoulder Impingement – 3 Keys to Assessment and Treatment

Shoulder impingement is a really broad term that is used too often. It has become such a commonly used junk term, such as “patellofemoral pain,” especially with physicians.

Other common variations include subacromial impingement or rotator cuff impingement, but it seems as if any pain originated from around the shoulder is often labeled as “shoulder impingement.”

Unfortunately, the use of such a broad term as a diagnosis is not helpful to determine the treatment process. There is no magical “shoulder impingement protocol” that you can pull out of your pocket and apply to a specific person.

I wish it were that simple.

This is also why conclusions are difficult to be drawn from meta-analysis and systematic reviews. A paper looking at hundreds of people age 25-65+ with “shoulder pain” isn’t going to provide much clarity, it’s too diluted.

Luckily, a thorough examination can be used to determine the best treatment plan. Each person will likely present differently, which will require variations on how you approach their shoulder rehabilitation.

Most of the clinical examination for shoulder impingement involves provocative tests. Those are great, but the real challenge when working with someone with shoulder impingement isn’t figuring out that they have shoulder pain, that’s fairly obvious. That’s why they are there.

It’s figuring out WHY they have shoulder pain, and what to do about it.

Shoulder Impingement: 3 Keys to Assessment and Treatment

To make the treatment process for shoulder impingement a little more simple, there are 3 things that I typically consider to classify and differentiate shoulder impingement.

  1. The location of shoulder impingement
  2. The structures involved
  3. The underlying cause of shoulder impingement

Each of these can significantly vary the treatment approach and how successful you are treating each person.

If you approach each patient with these 3 things in mind, you are going to do a much better job developing an effective treatment plan, versus just trying things and hoping they work.

I’ve called this the corrective exercise bell curve in the past. If you just throw the same treatments at every person with shoulder pain, you’ll probably get lucky 20% of the time, make them worse 20% of the time, and simply waste your time the rest.

Let’s dig in…

Location of Shoulder Impingement

The first thing to consider when evaluating someone with shoulder impingement is the location of impingement. This is generally in reference to the side of the rotator cuff that the impingement is located, either the outside of the rotator cuff or the undersurface of the rotator cuff.

These are broken down into either:

  1. Bursal sided shoulder impingement – this is your traditional subacromial impingement
  2. Articular sided shoulder impingement – this is called internal impingement
shoulder impingement - bursal articular side

Bursal Sided Shoulder Impingement

See the photo of a shoulder MRI above (photo credit). The bursal side is the outside of the rotator cuff, shown with the red arrow. This is probably your “standard” subacromial impingement that most people refer to when simply stating “shoulder impingement.”

This is often called subacromial impingement because of the location of impingement occurs between the rotator cuff and the undersurface of the acromion, hence the term “subacromial.” This is also called the bursal side of the rotator cuff because there is a bursa located between the rotator cuff and the acromion, which acts as a shock absorber.

Articular Sided Shoulder Impingement

The green arrow shows the undersurface, or articular surface, of the rotator cuff. This Impingement on this side is often termed “internal impingement” because the impingement occurs on the inside, or joint side, of the rotator cuff. If you look closely in the image above, the yellow arrow shows an articular sided partial thickness rotator cuff tear. Note the irregularity of white at the bottom of the dark line of the rotator cuff.

This often involves the supraspinatus and infraspinatus rotator cuff muscles as the undersurface impinges against the glenoid joint rim. I’ll go over this in more detail below.

The two types of impingement are completely different and occur for different reasons, so this first distinction is important.

Because the cause of shoulder impingement is so different, the evaluation and treatment of subacromial and internal impingement will also be completely different. More about these later when we get into the evaluation and treatment.

Impinging Structures Involved

The next factor to discuss is which structures are involved in the shoulder impingement. This is more for the bursal sided, or subacromial impingement, and refers to what structure the rotator cuff is impinging against.

Take a look at the shoulder from the side view, with the front of the shoulder to the right and the back of the shoulder to the left. You can see the acromion is superior and the coracoid is a little more anterior. The coracoacromial ligament runs between these two areas.

shoulder impingement - subacromial space acromion coracoid coracoacromial arch subcoracoid

As you can see in the image, your subacromial space is pretty small (the red areas). It’s pretty easy to impinge on the acromion, coracoid, or coracoacromial arch. There isn’t a lot of room for error. In fact, this really isn’t a blank “space”, there are actually many structures running in this area including your rotator cuff and subacromial bursa.

Get ready… I’m about to blow your mind…

You actually “impinge” every time you move your arm. We all do.

That’s right, impingement of these structures itself is normal and happens in all of us every time we use our arms. It’s when this becomes abnormal, excessive, or too frequent that shoulder pain and pathology occurs.

This is why it is very shortsighted to say “impingement” is normal and that people should work through their discomfort. Yes, some impingement is normal, but excessive impingement is what may cause pain and pathology down the road.

So when it comes to the structures involved in impingement, I try to differentiate between subacromial and coracoacromial arch impingement. These can happen in combination or isolation and typically involve the supraspinatus rotator cuff muscle.

Another area that has received more attention lately is the subcoracoid space or the area below the coracoid. You can also have subcoracoid impingement. Because this is located more anteriorly, the subscapularis rotator cuff muscle can be involved with subcoracoid impingement.

The three types of bursal sided impingement are fairly similar in regard to assessment and treatment, but I would make a couple of mild modifications for coracoacromial and subcoracoid impingement, which we will discuss below.

So if we were to get very specific, you can break shoulder impingement down into four different types based on the location and structures involved:

Bursal sided impingement:

  • Subacromial impingement – Involves the supraspinatus and acromion
  • Coracoacromial impingement – Involves the supraspinatus and coracoacromial arch
  • Subcoracoid impingement – Involves the subscapularis and coracoid

Articular Sided:

  • Internal impingement – Involves the supraspinatus and infraspinatus and glenoid rim

See what I mean? How can all of these be “shoulder impingement?” They all involved different muscles, different impinging structures, different locations, and different mechanisms!

OK, great, we now have differentiated and know “what” is impinging, we still don’t know “why” the person has impingement.

Cause of Shoulder Impingement

The next thing to look at is the actual reason why the person is experiencing shoulder impingement.

There are two main classifications of causes that I refer to as “primary” or “secondary” shoulder impingement.

Primary Shoulder Impingement

Primary impingement means that the impingement is the main problem with the person.

A good example of this is someone that has impingement due to anatomical considerations, with a hooked tip of the acromion like this in the picture below. Many acromions are flat or curved, but some have a hook or even a spur attached to the tip (drawn in red):

acromion tip hook osteophyte

This also happens with the coracoid and subcoracoid impingement. An anatomical variation of the coracoid or bone spur can be present.

As our knowledge of shoulder impingement improves, it appears that the larger a bone spur, the more problematic it may become.

This is referred to as primary impingement because improving things like mobility, strength, and dynamic stability may be ineffective as there is a primary cause of impingement causing the symptoms.

Sure we may improve the symptoms and often times are successful with rehabilitation, but sometimes we aren’t. It’s not because a certain treatment “isn’t effective for shoulder impingement.” It’s because there is a primary reason why impingement is occurring that we can’t change.

Without addressing the primary issue, like a large bone spur, working on secondary issues may not be effective.

Secondary Shoulder Impingement

Secondary impingement means that something else is causing impingement, perhaps their activities, posture, lack of dynamic stability, or muscle imbalances are causing the humeral head to shift in its center of rotation and cause impingement.

The most simple example of this is weakness of the rotator cuff.

The rotator cuff and larger muscle groups, like the deltoid, work together to move your arm in space.

The rotator cuff works to steer the ship by keeping the humeral head centered within the glenoid. The deltoid and larger muscles power the ship and move the arm.

Both muscles groups need to work together.

If rotator cuff weakness is present, the cuff may lose its ability to keep the humeral head centered. In this scenario, the deltoid will overpower the cuff and cause the humeral head to migrate superiorly, thus impinging the cuff between the humeral head and the acromion:

rotator cuff biomechanics - supraspinatus deltoid line of pull

This is just a simple example, but as you can see is very impactful for shoulder function. It’s not just weakness of the rotator cuff, it’s also imbalanced strength ratios and improper timing of dynamic stabilization.

Other common reasons for secondary impingement include mobility restrictions and poor dynamic stability of the shoulder, scapula, and even thoracic spine.

All of these areas need to work together to produce optimal shoulder function.

I see this a lot in my patients.

In the person below, you can see that they do not have full overhead mobility, yet they are trying to overhead press and other activities in the gym, flaring up their shoulder.

shoulder impingement overhead mobility

If all we did with this person was treat the location of the pain in his anterior shoulder, our success will be limited. He’ll return to the gym and start the process all over if we don’t restore this mobility restriction.

The funny thing about this is that people are rarely aware that they even have this limitation until you show them.

Also, keep in mind that this is not “chronic pain.” Sure this person has had shoulder pain for 8 months, but it’s because they keep irritating the area. This is more like recurring acute pain.

Differentiating Between the Types of Shoulder Impingement

In my online shoulder program on the Evidence Based Evaluation and Treatment of the Shoulder, I talk about different ways to assess shoulder impingement that may impact your rehab or training. There are specific tests to assess each type of impingement we discussed above.

The two most popular special tests for shoulder impingement are the Neer test and the Hawkins test.

In the Neer test, the examiner stabilizes the scapula while passively elevating the shoulder, in effect impinging the humeral head into the acromion.

In the Hawkins test, the examiner elevates the arm to 90 degrees of abduction and forces the shoulder into internal rotation, impinging the cuff under the subacromial arch.

As I mentioned earlier, these special tests for shoulder impingement are provocative in nature, meaning that we are looking for reproduction of pain.

Both of them will cause the structures to impinge in all of us, but they shouldn’t produce pain. But if the area is sensitive and irritable, they will cause pain.

You can alter these tests slightly to see if they elicit different symptoms that would be more indicative to the coracoacromial arch or subcoracoid types of subacromial impingement.

Because these structures are more anterior, we can alter the tests to better assess this area.

The Neer test can be performed in the sagittal plane, and the Hawkins test can be modified and performed in a more horizontally adducted position. Both of these positions will impinge more anteriorly.

shoulder impingement special test - hawkins kenedy test neer test.jpg

There is a good chance that many patients with subacromial impingement may be symptomatic with all of the above tests, but you may be able to detect the location of subacromial impingement (acromial versus coracoacromial arch) by watching for subtle changes in symptoms with the above four tests.

Now, before we go any further, let’s talk briefly about the reported accuracy of these tests in the literature.

Just like we’ve talked about with the studies looking at the treatment effectiveness in people with shoulder impingement, most studies published vaguely look at how accurate a test may be at detecting “impingement.” Hopefully, if you’ve gotten this far in the article, you see how flawed this approach is, as this is simply too broad.

How can we evaluate how “specific” a special test is for such a “non-specific” diagnosis?

Internal impingement is a different beast.

This type of impingement, which is most commonly seen in overhead athletes, is typically the result of some hyperlaxity of the shoulder in the anterior direction.

As the athlete comes into full external rotation, such as the position of a baseball pitch, tennis serve, volleyball serve, and others, the humeral head slides anterior slightly causing the undersurface of the cuff to impingement on the inside against the posterior-superior glenoid rim and labrum.

shoulder internal impingement

This is what you hear of when baseball players have “partial thickness rotator cuff tears” the majority of the time. They aren’t the same partial thickness tears your grandmother has.

The best special test for internal impingement is simple and is exactly the same as an anterior apprehension test.

The examiner externally rotates the arm at 90 degrees abduction and watches for symptoms. Unlike the shoulder instability patient, someone with internal impingement will not feel apprehension or anterior symptoms. Rather, they will have a very specific point of tenderness in the posterosuperior aspect of the shoulder (below left). When the examiner relocates the shoulder by giving a slight posterior glide of the humeral head, the posterosuperior pain diminishes (below right).

3 Keys to Treating Shoulder Impingement – How Does Treatment Vary?

Using the three main keys from the above information, you can alter your treatment and training programs based on the specific of impingement exhibited:

  1. The location of shoulder impingement – bursal or articular sided impingement
  2. The structures involved – Subacromial, coracoacromial arch, subcoracoid, or internal impingement
  3. The underlying cause of shoulder impingement – primary or secondary.

I promise you are going to have much more success in designing a physical therapy or training program if you factor in these keys.

Treating Different Types of Impingement

As I hope you can now see, to properly treat shoulder impingement you should differentiate between subacromial, coracoacromial, subcoracoid, and internal impingement.

Treatment is similar between these types of impingement. There is a bunch of overlap.

However, there are some differences:

  • With subacromial impingement, you should be cautious with overhead activities that produce discomfort
  • With the more anterior-based coracoacromial arch and subcoracoid impingement, you need to be cautious with elevation in more of a sagittal plane and horizontal adduction movements that produce discomfort
  • With internal impingement, you should be cautious with excessive external rotation at 90 degrees abduction (like the throwing position) that produce discomfort

Notice that I said “that produce discomfort” for all three? The key here for me is that you should not work through discomfort or a “pinch” with impingement.

A “pinch” is impingement of a sensitive structure!

I’m not a fan of working through pain with shoulder impingement. That to me shows me that you either have a primary or secondary cause of impingement that hasn’t been addressed. Trying to work through this could actually just irritate it more.

Treating Primary Versus Secondary Shoulder Impingement

This is an important one and often a source of frustration in young clinicians.

If you are dealing with secondary impingement, you can treat the person’s symptoms all you want, but they will come back if you do not address the underlying reason why they have symptoms.

But please remember, I do treat their symptoms, that is why they have come to see me.

I want to reduce discomfort and inflammation. This is going to allow me to do more in the long term. However, this should not be the primary focus if you want long term success.

This is where a more global look at the patient, their posture, muscle imbalances, and movement patterns all come into play. Breakthrough and see patients in this light and you will see much better outcomes.

You should have a systemized way of assessing movement and building programs to optimize and enhance their function. If you don’t you really should check out my system in my free online Introduction to Performance Therapy and Training course.

Introduction to performance therapy and training - laptop mockup

A good discussion of the activities that are causing their symptoms may also shed some light on why they are having shoulder pain.

Again, using the example above, if you don’t have full mobility and try to force the shoulder through this motion restriction you are going to likely cause some irritation.

This is especially true if you add speed, loading, and repetition, such as during many exercises in the gym.

I spend a great deal of time discussing what “zones” of motion the person should be working in. Essentially, I try to develop a “green zone” and a “red zone” depending on when they have symptoms.

Shoulder overhead elevation mobility

It’s important to continue working within their green zone and not simply say “take a few weeks off.” And slowly over time, our goal is to expand their green zone and reduce their red zone.

Treating Internal Impingement

Internal impingement involves a little more discussion. The main thing to realize with internal impingement is that this is pretty much a secondary issue. It is going to occur with any cuff weakness, fatigue, or loss of the ability to dynamically stabilize.

The overhead athlete will show some hyperlaxity in the “lay back” shoulder position of external rotation. Most overhead athletes have underlying laxity, what tends to happen is they lose strength or have an excessive workload that causes fatigue and then the structures impingement more and become irritable.

Treat the cuff weakness and its ability to dynamically stabilize to relieve the impingement. This often includes an initial period of rest and then building back their strength and dynamic stability.

How to treat internal impingement is a huge topic that I cover in a webinar for my Inner Circle members.

Learn Exactly How I Evaluate and Treat the Shoulder

If you are interested in mastering your understanding of the shoulder, I have my acclaiming online program teaching you exactly how I evaluate and treat the shoulder.

mike reinold shoulder seminar

The online program takes you through everything you need to become a shoulder expert. You can learn at your own pace in the comfort of your own home. In addition to shoulder impingement, you’ll learn about:

  • The evaluation of the shoulder
  • Selecting exercises for the shoulder
  • Manual resistance and dynamic stabilization drills for the shoulder
  • Nonoperative and postoperative rehabilitation
  • Rotator cuff injuries
  • Shoulder instability
  • SLAP lesions
  • The stiff shoulder
  • Manual therapy for the shoulder

The program offers CEU hours for physical therapists and athletic trainers. Click below to learn more:

Does Subacromial Decompression Surgery Really Do Anything?

Subacromial decompression surgery is a very common procedure performed for people with shoulder pain.  The procedure is often recommended for people with “shoulder impingement” and was originally theorized to open up the subacromial space and help reduce biomechanical impingement.  

But recent research has challenged the effectiveness of the procedure, and even the diagnosis of “subacromial impingement” itself.

Subacromial Decompression Surgery for Adults with Shoulder Pain: A Systematic Review with Meta-Analysis

A recent article in the British Journal of Sports Medicine reviewed the results of 9 clinical trials in over 1000 patients with shoulder pain.  The authors includes studies that compared subacromial decompression surgery with placebo surgery and exercise therapy.

The study noted that subacromial decompression surgery provided no important benefit compared with placebo surgery or exercise therapy. 

In particular, they found that surgery did not provide any additional benefit for pain, function, and quality of life at the 6- and 12-month mark after surgery.

As you can see, there does not appear to be a significant benefit in undergoing subacromial decompression surgery for shoulder pain or function.

What’s All This Mean?

Based on the results of several studies recently, it sure looks like we’re going to be seeing less subacromial decompression surgeries in the future.

It seems like the benefit of undergoing surgery may be related to the postoperative rehabilitation and application of graded exercise postoperatively.

This is another one of those surgical procedures that seems like it was missing the boat anyway.

Thinking purely biomechanically, rather than addressing the underlying concern that may be causing “impingement,” such as stiffness or loss of dynamic stability, we simply just make more space?  

Seems overly simplistic, right?

We probably haven’t address the underlying cause.

But based on all this, perhaps we shouldn’t even be using the term “impingement” anyway.

From a non-biomechanical perspective, I’m not even sure we truly understand the etiology of shoulder pain at times and always seem to rush towards a biomechanical “impingement” approach.  There could be numerous reasons why graded exercise can help reduce shoulder pain other than purely biomechanical factors.

But let’s not forget one main point here from this study.  At 5 years down the road, these patients still had shoulder pain between a 1.5 and 3 out of 10 on a visual analog scale.  

So advising people to ignore the biomechanics and simply work through some pain may not be an ideal approach as well.  

I’d hate to see us go down that road.

These patients had shoulder pain for greater than 3 months to be included in this study.  It’s difficult to quantify the degree of rotator cuff pathology present in these people, how this impacted their shoulder function, and what their long term prognosis will be going forward.  There is still underlying inflammation of the rotator cuff.

Image from Wikipedia

So What Should We Do?

As research like this continues to be published, we’re probably going to be seeing less of these procedures.

Maximizing the function of the shoulder is going to become even more important, regardless of whether or not something is causing “impingement.”  

I’ve had a lot of success with people by keeping it simple.  Rather than worry about the exact specifics of the pain, just simply focus on normalizing motion, increasing strength of the rotator cuff and scapular muscles, enhancing dynamic stability, and then gradually building tissue capacity through loading.

This is a great example of when focusing on the functional deficits is more impactful than the structural diagnosis.  

Optimize the person, don’t just treat the pain.

Shoulder Impingement – 3 Keys to Assessment and Treatment

Shoulder impingement really is a pretty broad term that most of us likely take for granted.  It has become such a junk term, such as “patellofemoral pain,” especially with physicians.  It seems as if any pain originated from around the shoulder could be labeled as “shoulder impingement” for some reason, as if that diagnosis is helpful to determine the treatment process.

Unfortunately, There is no magical “shoulder impingement protocol” that you can pull out of your notebook and apply to a specific person. [Click to Tweet]

I wish it were the simple.

A thorough examination is still needed.  Each person will likely present differently, which will require a variations on how you approach their rehabilitation.

But the real challenge when working with someone with shoulder impingement isn’t figuring out they have shoulder pain, that’s fairly obviously.  It’s figuring out why they have shoulder pain.

 

 

Shoulder Impingement: 3 Keys to Assessment and Treatment

To make the treatment process a little more simple, there are three things that I typically consider to classify and differentiate shoulder impingement.

  1. Location of impingement
  2. Structures involved
  3. Cause of impingement

Each of these can significantly vary the treatment approach and how successful you are helping each person.

 

Location of Impingement

The first thing to consider when evaluating someone with shoulder impingement is the location of impingement.  This is generally in reference to the side of the rotator cuff that the impingement is located, either the bursal side or articular side.

shoulder impingement assessment and treatment

See the photo of a shoulder MRI above.  The bursal side is the outside of the rotator cuff, shown with the red arrow.  This is probably your “standard” subacromial impingement that everyone refers to when simply stating “shoulder impingement.”  The green arrow shows the inside, or articular surface, of the rotator cuff.  Impingement on this side is termed “internal impingement.”

The two are different in terms of cause, evaluation, and treatment, so this first distinction is important.  More about these later when we get into the evaluation and treatment treatment.

 

Impinging Structures

To me, this is more for the bursal sided, or subacromial, impingement and refers to what structure the rotator cuff is impinging against.  As you can see in the pictures below (both side views), your subacromial space is pretty small without a lot if room for error.  In fact, there really isn’t a “space”, there are many structures running in this area including your rotator cuff and subacromial bursa.

Shoulder impingement

You actually “impinge” every time you move your arm.  Impingement itself is normal and happens in all of us, it is when it becomes excessive or abnormal that pathology occurs.

I try to differentiate between acromial and coracoacromial arch impingement, which can happen in combination or isolation.  There are fairly similar in regard to assessment and treatment, but I would make a couple of mild modifications for coracoacromial impingement, which we will discuss below.

 

Cause of Impingement

The next thing to look at is the actual reason why the person is experiencing shoulder impingement.  There are two main classifications of causes, that I refer to as “primary” or “secondary”shoulder  impingement.

Primary impingement means that the impingement is the main problem with the person.  A good example of this is someone that has impingement due to anatomical considerations, with a hooked tip of the acromion like this in the picture below.  Many acromions are flat or curved, but some have a hook or even a spur attached to the tip (drawn in red):

shoulder impingement

 

Secondary impingement means that something is causing impingement, perhaps their activities, posture, lack of dynamic stability, or muscle imbalances are causing the humeral head to shift in it’s center of rotation and cause impingement.  The most simply example of this is weakness of the rotator cuff.

The rotator cuff and larger muscle groups, like the deltoid, work together to move your arm in space.  The rotator cuff works to steer the ship by keeping the humeral head centered within the glenoid.  The deltoid and larger muscles power the ship and move the arm.

Both muscles groups need to work together.  If rotator cuff weakness is present, the cuff may lose it’s ability to keep the humeral head centered.  In this scenario, the deltoid will overpower the cuff and cause the humeral head to migrate superiorly, thus impinging the cuff between the humeral head and the acromion:

evaluation and treatment of shoulder impingement

 

Other common reasons for secondary impingement include mobility restrictions of the shoulder, scapula, and even thoracic spine.  We see this a lot at Champion.  In the person below, you can see that they do not have full overhead mobility, yet they are trying to overhead press and other activities in the gym, flaring up their shoulder.

shoulder impingement mobility

If all we did with this person was treat the location of the pain in his anterior shoulder, our success will be limited.  He’ll return to gym and start the process all over if we don’t restore this mobility restriction.

The funny thing about this is that people are almost never aware that they even have this limitation until you show them.

 

 

Differentiating Between the Types of Shoulder Impingement

In my online program on the Evidence Based Evaluation and Treatment of the Shoulder, I talk about different ways to assess shoulder impingement that may impact your rehab or training.  There are specific tests to assess each type of impingement we discussed above.

The two most popular tests for shoulder impingement are the Neer test and the Hawkins test.  In the Neer test (below left), the examiner stabilizes the scapula while passively elevating the shoulder, in effect jamming the humeral head into the acromion.  In the Hawkins test (below right) the examiner elevates the arm to 90 degrees of abduction and forces the shoulder into internal rotation, grinding the cuff under the subacromial arch.

Shoulder impingement tests

You can alter these tests slightly to see if they elicit different symptoms that would be more indicative to the coracoacromial arch type of subacromial impingement.  This would involve the cuff impingement more anteriorly so the tests below attempt to simulate this area of vulnerability.

The Hawkins test (below left) can be modified and performed in a more horizontally adducted position.  Another shoulder impingement test (below right) can be performed by asking the patient to grasp their opposite shoulder and to actively elevate the shoulder.

how to assess shoulder impingement

There is a good chance that many patients with subacromial impingement may be symptomatic with all of the above tests, but you may be able to detect the location of subacromial impingement (acromial versus coracoacromial arch) by watching for subtle changes in symptoms with the above four tests.

Internal impingement is a different beast.

This type of impingement, which is most commonly seen in overhead athletes, is typically the result of some hyperlaxity in the anterior direction.  As the athlete comes into full external rotation, such as the position of baseball pitch, tennis serve, etc., the humeral head slides anterior slightly causing the undersurface of the cuff to impingement on the inside against the posterior-superior glenoid rim and labrum.  This is what you hear of when baseball players have “partial thickness rotator cuff tears” the majority of time.

shoulder internal impingement

 

 

The test for this is simple and is exactly the same as an anterior apprehension test.  The examiner externally rotates the arm at 90 degrees abduction and watches for symptoms.  Unlike the shoulder instability patient, someone with internal impingement will not feel apprehension or anterior symptoms.  Rather, they will have a very specific point of tenderness in the posterosuperior aspect of the shoulder (below left).  Ween the examiner relocates the shoulder by giving a slight posterior glide of the humeral head, the posterosuperior pain diminishes (below right).

how to assess shoulder internal impingement

 

3 Keys to Treating Shoulder Impingement – How Does Treatment Vary?

There are three main keys from the above information that you can use to alter your treatment and training programs based on the type of impingement exhibited:

Subacromial Impingement Treatment

To properly treat, you should differentiate between acromial and coracoacromial impingement.  Treatment is essentially the same between these two types of subacromial impingement, however, with coracoacromial arch impingement, you need to be cautious with horizontal adduction movements and stretching.  This is unfortunate as the posterior soft tissue typically needs to be stretched in these patients, but you can not work through a pinch with impingement!

A “pinch” is impingement of an inflamed structure!

Also, I would avoid elevation in the sagittal plane or horizontal adduction exercises.

 

Primary Versus Secondary Shoulder Impingement

This is an important one and often a source of frustration in young clinicians.  If you are dealing with secondary impingement, you can treat the persons symptoms all you want, but they will come back if you do not address the route of the pathology!

I do treat their symptoms, that is why they have come to see me.  I want to reduce inflammation.  However, this should not be the primary focus if you want longer term success.

This is where a more global look at the patient, their posture, muscle imbalances, and movement dysfunction all come into play.  Break through and see patients in this light and you will see much better outcomes.

A good discussion of the activities that are causing their symptoms may also shed some light on why they are having shoulder pain.  Again, using the example above, if you don’t have full mobility and try to force the shoulder through this tightness you are going to likely cause some issues.  This is especially true if you add speed, loading, and repetition to elevation, such as during many exercises.

 

Internal Impingement

One thing to realize with internal impingement is that this is pretty much a secondary issue.  It is going to occur with any cuff weakness, fatigue, or loss of the ability to dynamically stabilize.   The athlete will show some hyperlaxity in this athletic “lay back” shoulder position.  Treat the cuff weakness and it’s ability to dynamically stabilize to relieve the impingement.  How to treat internal impingement is a huge topic that I cover in a webinar for my Inner Circle members.

 

Learn Exactly How I Evaluate and Treat the Shoulder

If you are interested in mastering your understanding of the shoulder, I have my acclaiming online program teaching you exactly how I evaluate and treat the shoulder at ShoulderSeminar.com!

The online program at takes you through an online 8-week program with new content added every week.  You can learn at your own pace in the comfort of your own home.  You’ll learn exactly how I approach:

  • shoulder seminarThe evaluation of the shoulder
  • Selecting exercises for the shoulder
  • Manual resistance and dynamic stabilization drills for the shoulder
  • Nonoperative and postoperative rehabilitation
  • Rotator cuff injuries
  • Shoulder instability
  • SLAP lesions
  • The stiff shoulder
  • Manual therapy for the shoulder

The program offers 21 CEU hours for the NATA and APTA of MA and 20 CEU hours through the NSCA.

Click below to learn more!

large-learn-more

 

Shoulder Impingement

Keys Shoulder Impingement

The latest webinar recording for Inner Circle members is now available below.

Shoulder Impingement

This month’s Inner Circle webinars discussed keys to shoulder impingement.  We talked about several topics, including:

  • Is shoulder impingement normal?
  • How to assess the different types of impingement
  • The three keys to treatment
  • The 5 “don’ts” of training around shoulder impingement
  • And more

To access the webinar, please be sure you are logged in and are a member of the Inner Circle program.

 

Rotator Cuff Fatigue Increases Superior Humeral Head Migration

shoulder impingementIf there is one thing that I would say is the most important concept to understand regarding the shoulder, it is simply that you can not work the rotator cuff to failure as rotator cuff fatigue causes superior humeral head migration and subacromial impingement.  That is it, I just summarized the role of the rotator cuff in one sentence, albeit a long sentence!

I talk about this concept all the time including a past post on humeral head biomechanics after rotator cuff fatigue, my Optimal Shoulder Performance DVD with Eric Cressey, as well as an entire week on rotator cuff injuries in my online shoulder CEU program.  Yet, I still read and see people performing exercises designed to “burn out” the cuff, or build endurance my “working the cuff to failure.”

This doesn’t work.  You can not work the rotator cuff to failure.

 

Rotator Cuff Fatigue Increases Superior Humeral Head Migration

Another recent study by Jaclyn Chopp from the Journal of Shoulder Elbow Surgery again contributes evidence to this concept.  The study examined the amount of superior humeral head migration during arm elevation in the scapular plane before and after fatiguing the rotator cuff.  The examiners fatigued the rotator cuff by performing a repetitive overhead lifting task that involved lifting an object in the following fashion:

  • Lifting an object from 45 degrees to 135 degrees of sagittal plane elevation
  • Then, slowly lowering the object in the same plane
  • Then, externally rotating the arm and lifting in the coronal plane
  • Then, slowly lowering the object again and internally rotating back into the original start position
  • Lastly, they also performed 5 second static holds at 90 degrees abduction with the same weight every minute.

As you can see, I like their fatigue protocol as it combines flexion, abduction, external rotation, and internal rotation of the shoulder, plus they threw in the commonly performed static hold at 90 degrees abduction.  The weight they lifted was 15% of their maximal lift, so certainly not that heavy and a good replication of a functional activity.

In the pre-fatigued state, the shoulder demonstrated normal biomechanics of a mild amount of superior humeral head migration that eventually stopped and centered the humeral head within the glenoid fossa.  This is normal, as the humeral head actually sits inferior to the center of the glenoid in the resting position, likely due to gravity.  So, you can see in the table below that the humeral head rises up a little and then actually migrated inferiorly as the arm is elevated.

In the fatigued state, the humeral head continued to migrated superiorly and never started to move inferiorly, effectively decreasing the subacromial space and potentially leading to shoulder impingement.

rotator cuff fatigue

 

superior humeral head migration

 

More evidence indeed to support the concept that the rotator cuff is so important in providing dynamic stability of the shoulder, even during simple tasks, that you can not work it to failure.  So think of this next time you want to attempt to work the cuff to failure. Doing so will increase superior humeral head migration and increase subacromial impingement.  So after that exercise, every time you pick up your arm for the rest of the day, you are causing some subacromial impingement.

So consider this a call to action, stop working the cuff to failure or performing burn out sets for the rotator cuff (and the back too, but that is another post…).  These muscles don’t work this way.  I continue to stick to sets of 10 repetitions for shoulder exercises.  I am also very careful when trying to build endurance in the rotator cuff, assuring that the person’s overall shoulder workload is not too high when focusing on endurance.

The last thing you want to do is cause rotator cuff fatigue, superior humeral head migration, or subacromial impingement.

Upper and Lower Trapezius Imbalances May Cause Subacromial Impingement

image A new journal article in Physical Therapy in Sport (the journal I recently reviewed) discusses imbalance between upper and lower trapezius muscle activity and the association of subacromial shoulder impingement.

The authors studied the EMG activity of the upper and lower trapezius in subjects with and without subacromial impingement.  Results show that subjects with impingement had a greater ratio of upper to trapezius to lower trapezius than the control group.  There was a large difference in group size (16 impingement subjects, 32 control), which is a limitation, I wonder why they choose to include so many controls.

Asymptomatic subjects had an upper trap (UT) to lower trap (LT) ratio of 1.80 while symptomatic subjects had a ratio of 3.15.  What this means is that the upper trapezius is a little more than 3 times more active than the lower trapezius during scapular plane elevation in patients with subacromial impingement.  This was a statistically significant finding.

Clinical Implications

I have noticed this imbalance in many shoulder patients as well and have always attempted to emphasize lower trapezius strengthening.  This is a part of what goes into my shoulder impingement treatments.

The authors also attempted to demonstrate that taping would then alter this imbalance and showed that upper trapezius activity was reduced after taping (lower trapezius remained the same).  While I commend the authors for attempting to tape and alter this imbalance, I would also state that this imbalance exists for a reason, and while it would be appropriate to try to reduce upper trapezius activity, I tend to focus on the following clinical guidelines:

  • Strengthen the lower trapezius.  This is a common area of weakness in shoulder patients.  See my article on shoulder exercises from JOSPT for some examples of good exercises for the lower trapezius.
  • Educate the patient during exercises to contract the lower trapezius and not the upper trapezius while elevating the arm.  I see this all the time.  I have even seen patients that attempt to “retract” the shoulder during exercises and inadvertently end up with predominantly the upper trapezius.  When you instruct people to “retract” or “pinch their shoulder blades” the emphasis should be back and DOWN.  I bet the majority of people will actually shrug their shoulders back and UP if not instructed properly.  I will work on a video of this to post over the next week or so.
  • Also consider the upper-cross syndrome.  This concept is discussed extensively in Janda and Chaitow’s works.  Inhibition of the lower trap is often associate with inhibition of the deep neck flexors and shortening of the pectoralis muscles, upper trapezius, and levator scapulae.  Attempting to address just one of these deficiencies will likely result in poor outcomes as the global issues have not all be corrected.  When you look at the image below, is it difficult to figure out why this is so prevalent in our population?

image    image

As this type of posture, muscle imbalance, and shoulder pain continue to become more and more prevalent in our society, what else have you done to try to help people like this?  What else have you focused on?

Fatigue of the Rotator Cuff Causes Altered Shoulder Mechanics and Impingement

Another interesting article from the most recent issue of Journal of Athletic Training on rotator cuff fatigue and glenohumeral kinematics. In this study, the authors used dynamic fluroscopic video to assess superior humeral head migration in 20 asymptomatic subjects before and after fatigue of the rotator cuff. The assessment of migration during a dynamic activity is a fairly novel approach as previous studies that have attempted to quantify superior humeral head translation have used static imaging such as radiographs and MRI.

During the study the authors used the prone horizontal abduction (with thumbs up) exercise to fatigue the cuff until there was a documented decrease of at least 40% strength. This was an important part of the study, as a reader I want to be sure that fatigue had occurred and a 40% drop is significant for me. I must say, though, that I wish the authors had performed a more specific rotator cuff exercise, such as simple external rotation. The prone exercise has shown EMG activity of the cuff but also the deltoid and scapula musculature.

Results of the study show that humeral head migration increased by an average of 0.79mm during elevation in a fatigued state. While this seems small, keep in mind that the average subacromial space is between 2mm and 14mm in healthy subjects (can be about 50% smaller in pathological patients), thus reducing subacromial space by up to 40%!

Clinical Implications

RTC fatigue can lead to shoulder impingement
. An interesting component of the article that the authors did not bring up in their discussion was that the humeral head actually migrated inferior prior to fatigue as the RTC acted to maintain the humeral head within the glenoid fossa as the deltoid provided a superior orientated force vector. After the fatigue, not only did the humeral head not migrate inferior, it moved superiorly. This has obvious implications for subacromial impingement. Both strength and endurance of the cuff should be addressed in rehabilitation, makes sense why a deconditioned person so much more likely to develop shoulder impingement.

The rotator cuff should never be worked to failure. The fatigue protocol used by the authors lasted for less than 90 seconds. That is all it took for the RTC to loose 54% of it’s strength. Now think about that last time you had a patient come to you with “impingement” that reported playing tennis or golf for the first time in months, or even more simply, painting a room in their house. With only 90 seconds of activity the cuff fatigue enough to decrease your subacromial space by up to 40%. What should your treatment be for that patient? Minimize the initial inflammation, work on cuff strength & endurance but by all means, DON’T work the cuff to failure.

The rotator cuff should NEVER be worked to failure!

I never understood this training technique. If you work the cuff to failure, then what is going to dynamically stabilize the humeral head later that day when you a reaching overhead?

As always, please comment with your thoughts and experience!