Tag Archives: shoulder mobility

Internal Impingement of the Shoulder – PART IV

Last week we visited external impingement in the shoulder, how it arises, and what to do.  This week we’ll take a look at internal impingement.  Internal impingement is a pathologic condition that can lead to a whole host of problems in the shoulder.  The problem is most commonly seen in overhead throwing athletes, tennis players, volleyball players, swimmers, as well as athletes involved in overhead weight lifting. 

Shoulder Mobility and the Fist to Fist PART I

Shoulder Series and the Sleeper – Part II

External Impingement – PART III

Internal impingement is the repetitive contact of the articular surface of the rotator cuff against the posterior superior surface of the glenoid and glenoid labrum.  Essentially, the supraspinatus and infraspinatus become trapped between the humeral head and the rim of the glenoid in the back of the shoulder.  This happens when the arm is abducted and externally rotated or the “high 5” position as I like to refer to it.  When we look at sporting activities this encompasses it’s the exact position for throwing, or serving in tennis. 

Internal impingement of the shoulder: comparison of findings between the throwing and nonthrowing shoulders of college baseball players

Contact between these structures happens naturally but not everyone presents symptomatic with pain.  When internal impingement is ignored rotator cuff and labral fraying can occur which can lead to full on cuff tears SLAP tears, and labral lesions; not a good thing for the shoulder. 

The precise cause of these impingement lesions remains unclear. However, it is believed that varying degrees of glenohumeral instability, posterior capsular contracture, and scapular dyskinesis may play a role in the development of symptomatic internal impingement.

Overhead athletes are pre-disposed to internal impingement purely because of the physiologic adaptations that they develop which include humeral retroversion, anterior laxity, increased external rotation, etc.  The same characteristics that allow an individual to throw hard also cause dysfunction in the shoulder. 

When pitchers lay back into maximal external rotation the head of the humerus is allowed to slide anteriorly in the gleniod.  With the inability to stabilize the humerus dynamically at high speeds the posterior cuff gets pinched between the gleniod and the humerus.  Athletes usually complain of pain on the posterio-superior region of the shoulder when the arm is externally rotated into the throwing position. 

Exact causes of internal impingement aren’t exactly clear but there are several theories on what causes internal impingement but most start with anterior laxity, the inability of the rotator cuff to stabilize dynamically, scapular dysfunction, as well as posterior tightness. 

The first place to start in the rehabilitation of internal impingement symptoms is to restore total motion to the glenohumeral joint, namely the posterior musculature.  This can be done by stretching with the sleeper stretch as well as cross body adduction. 

From there we also want to emphasize strengthening the rotator cuff statically, then dynamically.  Anything to strengthen the cuff and major players in the role of proper scapular function is warranted, especially upward rotation. 

The one thing we don’t want to emphasize is any external rotation stretching.  The anterior capsule is already loose enough due to the nature of their skill.  When we stretch we are concerned with increasing movement through internal rotation. 

The main take home points for internal impingement are to restore motion, especially internal rotation, strengthen the cuff and scapular stabilizers, and look to restore proper motion in the scaps.

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Shoulder Mobility and the Fist to Fist PART I

Since the first week of school is upon us this means one thing for the baseball program at TCU; movement screens.  The last 4 days of my life have been evaluating, measuring, and deciphering movement.  I recently uploaded a few videos that give some quality examples of the overhead squat, both good and poor.  I’ll post on those in the next couple days or so. 

Today, I wanted to talk about the fist to fist test that some use, including myself, to measure shoulder mobility. 

The problem with the fist to fist is that it isn’t a true indicator of shoulder mobility, and more specifically, glenohumeral internal rotation.  There are a number of factors that play into being able to raise the hand high on the back.  A combination of elbow flexion, scap movement, and internal rotation all play a part. 

Several years ago when I first began administering the fist to fist test for shoulder mobility I had an individual measured 5 cm with the right arm up, and 7 cm with the left arm up.  According to Gray Cook and the FMS this is scored a 3 and shows great ROM with no imbalances to speak of.  At that time I utilized this test exclusively for our shoulder ROM and didn’t perform any added measurements so to speak when an athlete scored perfectly on his gross movement tests.  However, this individual later ended up having an issue during the season and consequently had to be scoped following the year with a partial rotator cuff tear. 

On the surface throughout this athlete’s testing, and screening he didn’t show any disposition to a lack of shoulder ROM.  However, when he was looked at by our team shoulder specialist he had a large glenohumeral internal rotation deficit as well as a total arc deficit which we now know as a huge indicator of problems in the throwing shoulder. 

At the time I couldn’t quite understand how an athlete can score so well in shoulder mobility and then have such restrictions at the same time, but I soon began to dig deeper. 

A study done in 2006 by Karen Ginn in the Journal of Shoulder and Elbow Surgery showed the behind the back reach test to have a low to moderate correlation with true shoulder internal rotation. 

Does hand-behind-back range of motion accurately reflect shoulder internal rotation?

In an even more specific study done back in 1996, the examiners discovered that the more correlated movement occurs in the scapulothoracic area when high results are achieved with the behind the back test of shoulder mobility, and that the majority of shoulder internal rotation occurs while the arm is still in front of the body.

Use of vertebral levels to measure presumed internal rotation at the shoulder: A radiographic analysis

What these studies tell us are that the scapula, and elbow to a lesser extent accounts for more of the motion in the test than true internal rotation occurring at the shoulder. 

The video above is a great example of what I’m talking about.  The athlete measures well under 10 cm on both sides exhibiting no imbalances and showing great shoulder mobility . . . right?  When you have the athlete remove his shirt the problem is easily identified.  The movement occurs because of the scaps inability to stay stable thus allowing the athlete to get his hands so close in the screen.  The actual movement isn’t occurring in the shoulder.  This athlete is in dire need of some scapular stabilization work here. 

When we dig deeper with a goniometer and passive internal, and external rotation we find our real issues.  This particular athlete is right handed pitcher with measurements as follows:

Right
External: 129 deg.
Internal: 48 deg.
Total Rotation: 177

Left
External 125 deg.
Internal 65 deg.
Total Roation: 190

We now undercover the truth of his actual glenohumeral motion.  This athlete has a total rotation deficit of 13 degrees and a glenohumeral internal rotation deficit of 17 degrees.  When all looks good on the fist to fist we actually find that this athlete has lost ROM in his throwing arm which is a huge indicator of shoulder injuries in throwing athlete.  I actually don’t even want him throwing a baseball until we recover that lost motion.  It’s that important.  Now, had we not actually measured rotation at his shoulder we would have cleared him with flying colors because of his fist to fist test.  This is where the fist to fist can and does commonly cause problems.  In the past few years I have learned a lot exponentially more about the shoulder and have come to understand why the fist to fist test leaves so much to be desired.