Let's talk about the true role of the rotator cuff and why isolated cuff training may not be right for most people.  I've run into a few patients lately presenting with shoulder pain due to isolated banded rotations and front and lateral deltoid raises.  These patients are otherwise completely healthy athletes but with good intentions tried exercise to preventatively strengthen the rotator cuff.  Almost ironically the exercises lead to shoulder pain, but why?  

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The supraspinatus, infraspinatus, terres minor, and subscapularis make up the rotator cuff.  In isolation they do provide rotation about the joint but are these muscles truly prime movers or stabilizers?  In this case the true role of the cuff is to provide dynamic compressive stability to the glenohumeral joint.  All the muscles must act in three planes, if the infraspinatus is causing external motation the other cuff muscles are helping maintain stability in the other two planes.  Working together the muscles of the cuff act to pull the humerus into the glenoid and provide stability.  A baseline of strength is absolutely required to provide this stability and this is where isolation work is beneficial,  but as soon as adequate strength is achieved functional exercise incorporating thoracic and scapular control is required to train the body to move the arm ideally.  The difference between these exercises may be as simple as going from side lying to kneeling, or adding a press after external rotation.  These subtle changes provide a much different demand and stimulus to the body allowing you to develop strength symmetrically.  

The importance of the scapula in cuff control cannot be understated, but is a topic for another blog.  All four muscles of the rotator cuff originate on the scapulae, and is a major component in energy transfer centrally to the arm, so you can imagine why proper scapular positioning and control is vital in a comprehensive upper extremity program.

Going back to the previously mentioned patients, they have acquired baseline strength in these muscles but they are trying to add isolated strength in one plane and neglecting the true roll of the cuff which is causing muscle imbalance and eventually dysfunction.  I think these patients would be better off with exercises that focus on use of the kinetic chain and global thoracic, scapular, and gelnohumeral movement.   Again, isolation cuff exercises are not worthless by any means, they serve a very specific purpose, to help achieve adequate strength in order to provide stability.

I came across a news program recently which was doing a segment on a gym whose entire premise is slow motion training.  In the segment the clients were only shown doing isolation cuff exercises very slowly.  You now know why this is slightly disconcerting and very likely not appropriate for most clients.

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Exciting Research

Numerous studies have indicated a rotator cuff surgery failure rate anywhere from 25% - 90%.  Anecdotally, I underwent glenoid labrum reconstruction surgery as a result of a high school wrestling injury which failed 6 months later.  Recently there has been some very exciting research in which physical therapy improved outcomes of pain, mobility, and function and prevented surgery in 75% of patients.  The results of this study clearly indicate that we should attempt physical therapy before surgical repair of rotator cuff tears.

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References

  • Baskurt: J back MS rehab 2011
  • McClure: PT 2004

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