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

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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