Does Reaching Behind the Back Actually Measure Shoulder Internal Rotation?


It’s no secret that I’m not a big fan of stretching the shoulder behind the back to gain internal rotation.  I have written about this in the past and even included it in my list of 5 least favorite exercises.  I received a lot of feedback for this opinion, both positively and negatively. 

Many people agree with me that this is an aggressive stretch and puts the rotator cuff in an extremely disadvantageous position, while many argued that it is still a position of function for their patients.

I completely agree that this is an important functional position, but that doesn’t mean that reaching behind the back accurately reflects shoulder internal rotation, or that stretching in this position is effective, without being disadvantageous.

Apparently, I am not the only one who has questioned this in the past as I have come across some research studies that assess if reaching behind the back is an accurate measurement of internal rotation. 

What Does the Research Say?

Wakabayashi et al (JSES 2006) used electromagnetic tracking to assess the amount of shoulder internal rotation, extension, adduction, and elbow flexion while reaching behind the back.

The authors report that the majority of internal rotation at the shoulder occurs before the patient reaches the sacrum.  There is also a significant increase in shoulder extension and adduction to reach the sacrum.   After the hand passes the sacrum, the majority of motion is achieved by flexing the elbow.  After the hand passes T12, there is no significant increase in internal rotation. 

So it appears that getting to the sacrum is the key to this motion and that shoulder internal rotation, adduction, and extension can all limit the ability to get to the sacrum.

Mallon et al (JSES 1996) used radiographs in healthy individuals to assess contributing motions while reaching behind the back. The authors concluded that 35% of the motion actually occurs at the scapulothoracic joint, and not the shoulder.  They also agreed that elbow flexion was an important component of this motion and considered the behind-the-back position to be invalid for measuring shoulder internal rotation. 

Another study by Ginn et al (JSES 2006) assessed the validity of the behind-the-back motion in assessing a loss of internal rotation in a group of 137 subjects with shoulder pain.  The authors measured the behind-the-back motion as well as standard goniometry of shoulder internal rotation at 45 and 90 degrees of abduction.  The results showed only a low to moderate correlation between the motions, but more importantly, the ability to reach behind the back did not correlate to loss of active internal rotation of the shoulder.

Clinical Implications

So what does all of this mean?  Here are my thoughts:

  • Reaching behind the back is not a valid measurement for internal rotation.  The motion is created by the combination of scapula tilt, shoulder internal rotation, adduction, extension, and elbow flexion.  Any combination of these factors will influence this motion.
  • Be careful when using a shoulder outcome scale that uses the this motion to quantify shoulder internal rotation.  Unfortunately some do, including the Constant scale and the American Shoulder Elbow Surgeons (ASES) scale.
  • If you want to measure internal rotation of the shoulder, actually measure internal rotation of the shoulder.  Grab that old goniometer out of the dusty drawer, it is actually pretty handy!
  • Don’t make treatment implications based on the behind-the-back motion.  For example, don’t perform posterior capsule joint mobilizations on a person just because they can’t reach behind their back. Assess, don’t assume!

How to Improve Reaching Behind the Back

Based on all of this, what about the person that has a limitation reaching behind the back, what should we do?

  • I understand and agree that this is a position of function.
  • I still recommend avoiding this as a stretch.  I have never had good outcomes and I really believe you are putting the shoulder joint and rotator cuff in a disadvantageous position.
  • Use the information from these studies to explore why a person doesn’t have the ability to reach behind their back.  Assess the scapula, shoulder extension, asduction, and elbow flexion.  Which of these movements are limited? Don’t just assume it is all internal rotation.

That’s my approach to helping people improve reaching behind their back. I break down each of the individual motions of the scapular, shoulder, and elbow, and then treat any limitations I find.

Often times by focusing on the individual motion that is limited, you’ll improve on your functional ability to reach behind your back.

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