Sports Medicine Research: In the Lab & In the Field: Wasted Effort or Useful Technique – What's The Truth About Scapular Repositioning and Muscle Activation (Sports Med Res)


Friday, December 14, 2012

Wasted Effort or Useful Technique – What's The Truth About Scapular Repositioning and Muscle Activation

Conscious Correction of Scapular Orientation in Overhead Athletes Performing Selected Shoulder Rehabilitation Exercises: The Effect on Trapezius Muscle Activation Measured by Surface Electromyography

De Mey K, Danneels LA, Cagnie B, Huyghe L, Seyns E, Cools AM. J Orthop Sports Phys Ther. 2012 Nov 16    

Once generally overlooked, the role of the scapula has become the focus of many injury prevention and sports performance programs.  In order to achieve neuromuscular control and dynamic stability, programs call for some level of conscious scapular neutral positioning prior to exercise.  However, it is unclear if this affects the main scapular rotators (trapezius muscles) during loading.  Therefore, the purpose of this study was to examine the effect of conscious scapular positioning on upper (UT), middle (MT) and lower trapezius (LT) activity during 4 loaded exercises performed by overhead athletes presenting with scapular dyskinesis.  Thirty participants were recruited for this study and demonstrated altered scapular resting positions as well as altered scapular dyskinesis upon dynamic clinical exam.  Scapular dyskinesis was categorized as Type 1- prominence of the inferior medial scapular angle, Type 2 – the entire medial border or Type 3 – the superior border of the scapula.  Each subject participated in one of the following overhead sports: volleyball, swimming or badminton.  Electromyography was recorded for the UT, MT and LT.  Each participant performed baseline testing consisting of prone shoulder extension, side-lying external rotation, side-lying forward flexion, and prone horizontal abduction with shoulder external rotation; without conscious scapular positioning.  Each exercise was performed with a hand weight as determined by a gender and body-weight scale. Five 3-second concentric bouts were performed for each exercise with 3 seconds rest between each bout. The participants were given 2 minutes of rest between each exercise.  For the test conditions, the participants underwent visual, auditory, and kinesthetic training based on their scapular dyskinesis category until they could satisfactorily hold a scapular neutral position for 5 seconds.  The same 4 exercises were then randomized and repeated.  Because participants were unable to consciously correct scapular patterns over a total range of motion, the exercises were limited to 90 degrees. When scapular neutral positioning became impaired, the participants were given appropriate verbal cues.  Results showed significant levels of increased muscle activation in all 3 areas of the trapezius for prone extension and side-lying external rotation when consciously correcting scapular position versus baseline.  Conversely, there was no significant interaction between scapula orientation and muscle activity for side-lying forward flexion and prone horizontal abduction with external rotation.

Although adjusting scapular orientation during shoulder exercises to improve neuromuscular control has become more common place in our rehabilitation efforts, these results demonstrate that it is exercise dependent.   One short coming of this study is the 2 testing conditions (baseline and conscious correction).  While the baseline tested UT, MT, and LT activity across a full range of motion, the experimental conditions did not.  Cutting the test exercises off at 90 degrees of their respective range of motions does not accurately portray a sport-specific scenario.  Overhead athletes typically engage in their respective sporting tasks well above 90 degrees of abduction.  For the testing conditions to have been more relevant to the sporting world, measuring the muscle activity at higher degrees of abduction would be necessary.  Conversely, many therapeutic exercises occur at 90 degrees of abduction and below, so the utility of these findings is not lost.  The question remains, “Should we continue with scapular repositioning for all exercises to elicit increased muscle activity, or should we be more selective of the exercises when applying conscious repositioning techniques”? What are your thoughts on this study?  What is your philosophy on scapular repositioning when comes to your injury prevention and/or rehabilitation efforts?

Written by: Mark Rice
Reviewed by: Stephen Thomas

Related Posts:

De Mey K, Danneels LA, Cagnie B, Huyghe L, Seyns E, & Cools AM (2012). Conscious Correction of Scapular Orientation in Overhead Athletes Performing Selected Shoulder Rehabilitation Exercises: The Effect on Trapezius Muscle Activation Measured by Surface Electromyography. The Journal of Orthopaedic and Sports Physical Therapy PMID: 23160271


Kyle Kosik said...

I use scapular repositioning and rotator cuff exercises when working with my pitcher in the off-season and during rehab. I think using scapular repositioning is a great exercise and I have seen great results from using it in a lot of my pitchers. From my experience, it takes more than just one session of showing athletes how to properly recruit all of your muscles surrounding the shoulder. I have to continually monitor my athletes while they do there of scapular repositioning exercises because they routinely perform the exercises incorrectly. I think it would be interesting to perform a study looking at individuals who have repetitively performed scapular repositioning exercises vs. those who have not, and look at the differences between the two groups.

Kale Songy said...

I think that scapular repositioning exercises are more of a matter of activating muscles that are not used efficiently. I view these strengthening programs more as muscle re-education programs. The largest benefit I have seen from implementing these programs has been a decrease in pain, not necessarily hypertrophy of muscle or altered posture.

Mark A. Rice said...

Kyle and Kale, thanks for taking the time to read and comment. I believe that scapular repositioning exercises ARE a good adjunct to UE rehab. Building a strong foundation can and will have a positive impact on performance and shoulder health. However, does it need to be performed with all of our UE exercises or just select ones? I agree that it is something that needs to be committed to, as you say. Taking a a 1 and done attitude definitely won't get the athlete where they want to be. There is definitely a learning curve. More research needs to be conducted to determine which other exercises are positively impacted by scapular repositioning.

Kale, I couldn't agree more. The scapular rotators and stabilizers are more about function than form. Those muscles were put in place to perform a specific job, not for hypertrophic/showing-off reasons. While many people can go to the gym and increase muscle mass, the cross sectional area of muscles like the serratus anterior (Functional muscle) isn't as great. The SA has a specific job to do, and brute strength isn't it. Sure, strength and some size can be added with commitment, but in the end it's role is a bit more complicated than just adding size and strength.

Lindsy said...

I agree with both Kyle's and Kale's comments. I too have see positive improvements in reported outcomes and function in my overhead athletes when they improve scapular strength and function. It is also imperative to monitor and correct them throughout their program to ensure they are using correct form consistently in order to elicit muscle memory and retrain the scapular stabilizers. As with any rehabilitation program, if you allow a person to strengthen in an inefficient position then you are training them to perform in a position of dysfunction. Mark, you raise a really good question. I believe it is imperative to emphasize a neutral scapula for all UE exercises, regardless of a lack of significance in activation relative to certain positions.

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