Acromiohumeral Distance in Overhead Athletes With Glenohumeral Internal
Rotation Loss and the Influence of a Stretching Program

A, Van Eessel V, Van Dyck L, Vanraes A, Cools A.  Am J Sports Med. 2012 Aug 6. [Epub ahead of

is well known that overhead athletes develop a loss of internal rotation (IR; also
called glenohumeral internal rotation deficit or GIRD) and a gain of external
rotation (ER).  Recently, it has been
demonstrated that baseball players with GIRD are more likely to develop
shoulder injuries.  It has been suggested
that GIRD is caused by a tight posterior capsule and during ER the tight
capsule may alter the arthrokinematics of the shoulder by moving the head of the
humerus in a posterior-superior direction thereby decreasing the acromiohumeral
distance (AHD).  However, it currently
unknown if this occurs and if stretching of the posterior shoulder improves
motion and the AHD.  Therefore, the
purpose of the study was to compare bilateral AHD in overhead athletes with
GIRD (> 15° loss of IR) and to examine the effect of the sleeper stretch
on AHD and IR.  The authors assessed bilateral
range of motion (IR, ER, and horizontal adduction) in the supine position with
the scapula stabilized among sixty-two overhead athletes with GIRD.  AHD was measured using diagnostic ultrasound
at rest, 45°, and 60° of abduction.  Athletes
were then randomly divided into a stretching (n = 30) or a control (n = 32)
group.  The stretching group performed
the sleeper stretch daily (3 reps of 30 sec holds) for 6 weeks on the dominant
arm.  All stretching was performed by the
athletes with no sessions from physical therapists or athletic trainers.  The control group did not perform the sleeper
stretch but were asked to maintain normal activities.  Range of motion and AHD were reassessed after
the 6-week intervention period.  At
baseline, the authors found that dominant arms’ IR and horizontal adduction
were significantly less and ER was greater compared to the non-dominant for
both groups.  Also, AHD was smaller on
the dominant arm compared to the non-dominant. 
When examining the effect of stretching there was a significant increase
on the dominant arm for IR, horizontal adduction, and AHD at all
positions.  There were no changes on the
dominant arm of the control group. 

study is the first to demonstrate that the dominant shoulders of overhead
athletes with GIRD have reduced AHD compared to the contralateral shoulder and
that sleeper stretching improves the AHD in just 6 weeks.  Clinically, this is a very important finding
which gives support for both the hypothesis that GIRD will cause a decrease in
AHD and that stretching not only improves ROM but also increases the AHD.  A loss of AHD has been suggested to cause
impingement of the rotator cuff and lead to tendon degeneration or even
tears.  Maximizing the AHD may minimize
the risk of impingement and maintain the health of the rotator cuff.  Previous research has found that GIRD can
increase the chance of shoulder injury. 
By performing the sleeper stretch the athlete can eliminate GIRD and
increase AHD thereby reducing the likelihood of injury; however, more research
may be needed to verify the reduce risk of injury.  One limitation of the study was that AHD was
not assessed at 90° of abduction which is the functional position of overhead
athletes.  However, based on their data
there was a significant improvement at all of the tested shoulder positions up
to 60°.  This may suggest that a similar
finding would have occurred at the 90° position.  It would also be interesting to examine other
methods to increase IR in overhead athletes (posterior joint mobilizations,
active release, etc).  A nice follow-up
to this study would be to follow these athletes over the season to evaluate
injury rates.  What are your thoughts on
this study?  Do you currently use the
sleeper stretch or do you have other ways to reduce GIRD?  Do you think a decrease in the AHD contributes
to shoulder injuries in overhead athletes with GIRD?

by:  Stephen Thomas
by:  Jeffrey Driban


Maenhout A, Van Eessel V, Van Dyck L, Vanraes A, & Cools A (2012). Quantifying acromiohumeral distance in overhead athletes with glenohumeral internal rotation loss and the influence of a stretching program. The American Journal of Sports Medicine, 40 (9), 2105-12 PMID: 22869627