Rotator Cuff EMG During Daily Activities

DSC01454A frequent topic of discussion on this site involves the postoperative guidelines following rotator cuff repair.  We have had many discussions about the contrast in preference between early rehabilitation and conservative rehabilitation among clinicians.  Obviously, if you have read some of my past posts and publications (check out here and here), you know that I have always preferred to start immediate rehabilitation and have had pretty good success.

However, many, many clinicians are still progressing conservatively, even delaying the initiation of range of motion for 2 months and strengthening exercises for 3+ months!  The common justification is to avoid deleterious forces on the repair in attempt to minimize failure of the repair.  A few studies have been published showing that anywhere from 25-75% of rotator cuff repairs are torn again 1-2 years after repair.

That is why a recent study in JOSPT was of interest to me.  The study quantified the EMG activity of the infraspinatus, supraspinatus, and deltoid musculature during the pendulum exercises and three activities of daily living – typing, drinking from a glass, and brushing your teeth.  These are all activities that our rotator cuff repair patients are performing and an exercise, the pendulum, that I would say most physicians are comfortable allowing early in the rehabilitation process.

Results

The results of the study were very interesting, highlights include:

  • Pendulums were broken down into 4 groups and compared.  These included large circles and small circles as well as performed passively (correctly) or actively (incorrectly).
  • Large circles in general created higher EMG activity of all muscles involved.
  • Large circles performed actively produced the highest amount of supraspinatus EMG activity – about 19% MVIC
  • Small circles produced less than 10% MVIC of the deltoid and supraspinatus, and under 15% MVIC of the infraspinatus
  • Typing had relatively low EMG activity with 12% MVIC infraspinatus and 7.5% MVIC supraspinatus
  • Brushing your teeth showed 20% MVIC of the infraspinatus
  • Drinking from a glass showed over 18% MVIC of the infraspinatus and 21% MVIC of the supraspinatus

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Clinical Implications

There are a few major points I took away from this study

  1. Pendulums should be performed using small, rather than large, circles.  Furthermore, it is important to instruct the patient in proper technique, using the body to sway the shoulder passively rather than actively perform circles.  We have all seen patients just actively twirl the arm around.  This was never the true intent of the pendulum exercises.  It’s true form should be passive.  Here is a good example:
  2. Some common ADL’s, including brushing your teeth and drink from a glass, show higher EMG activity than pendulums.
  3. Furthermore, if you combine this information with past studies by McCann (CORR ’93) and Dockery (Ortho ‘98), these common ADL’s also have higher EMG activity than passive and active assisted range of motion exercises.  Thus, it again appears that we have more information to justify the use of early range of motion exercises following rotator cuff repair.

Interesting information.  How many people have physicians that will allow pendulums but will not let you start passive range of motion early after rotator cuff repair?

5 replies
  1. Ryan, DPT, MTC
    Ryan, DPT, MTC says:

    One of the biggest concerns I have is that this study looked at circular pendulums, and not the pendulums demonstrated in the video. I am a USA grad and Stanley Paris was very adamant about NOT performing circles. His instruction was to perform them as the video showed, in a linear direction, causing the repetitive and constant changing of direction and velocity. The theory behind this was that less mechanical receptors were activated during circles due to the constant direction and velocity. I would like to see what the EMG study showed with the pendulums performed like the video. Any studies out there looking at that? Anyone agree with the study stating that “correct” pendulums were the smaller passive circles? Is there disagreement in what I stated above?

  2. Brian Phillips
    Brian Phillips says:

    The MD's we work with send all of their cuff repairs to begin PT within a week of surgery. We have had very good results with beginning PT immediately vs waiting 6 weeks or more to start PROM stretching.

    The pendulum exercise is an integral part of our Phase 1 rehab to help restore ROM and decrease pain (as well as being a good position to allow to wash the armpit/put on deodorant of the surgical arm). However, we DO teach the pendulum exercise “incorrectly” according to this study and allow the patient to stand still and lean forward and perform small active circles with the arm. Our instruction is to make a small circle “no larger than a Coke can or small dessert plate.” Again, the emphasis is a very small circle. Part of our reasoning behind this is that following surgery many people are not able to fully relax their arm and allow it to sway back and forth as the man in the video demonstrated. Thus, even though you are instructing them to make a passive circle with their arm, it ends up being an active, or at least active-assisted exercise. Two, some of our patients lack the coordination or balance to sway their body back and forth, and would thus become a fall risk to potentially further injure themselves. Finally, according to this study, “incorrect” small pendulums demonstrated only a 0.7% increase in Supraspinatus MVIC and actually had a lower MVIC for the Infraspinatus than “correct” small pendulums.

    The main thing for me is that our patients usually end up LOVING how the pendulum makes their shoulder feel after about post-op week one and willingly continue to perform them for nearly their entire stay of therapy.

    Two limitations of this study that the author’s did point out were that “the activity of the shoulder muscles in healthy subjects may not be representative of the activity of individuals with a repaired rotator cuff muscle,” and that “the average age of the volunteers is younger than the average age of patients undergoing rotator cuff surgery.”

  3. Anonymous
    Anonymous says:

    I should also add that for other types of shoulder injuries this surgeon does do some exercises immediately post op (passive range of motion).

  4. Anonymous
    Anonymous says:

    I had a shoulder reconstruction for a torn labrum (from about 4oclock-8oclock) in August 2008. I had my operation performed by a surgeon who is considered one of the best in Australia and is known for being very strict and conservative in regards to his rehab protocol.

    I was in a sling for nearly 6 weeks post op and I was not allowed to perform any exercises during that period (all I could do was take my arm out of the sling to straighten my elbow to relieve discomfort).

    Once the near 6 week period was up I then started on pendulum swings, which progressed to some stretching exercises and some band work.

    After about 12-14 weeks of following the surgeon's protocol for rehab as well as swimming after about 6 weeks (breast-stroke) I was then given the clearance to start physio.

    After going through 2 physios I finally found one who was able to get me back to the baseball field to play, and I am now doing maintenance exercises 1-2 times per week as well as doing strength training in the gym).

    It's taken nearly 2 years to get back this far, but I was not in any rush to get back compared to a professional athlete.

    If I could do it again I would have chosen the physio who helped me get back and probably saved 6+ months, but the important thing for me is that I am pain free and able to train and play sport again.

    With the success of the repair I am fine with following the conservative approach, but I am also a patient who will do every exercises to the letter, I think this is the key to returning to previous levels of activity.

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