Risk factors associated with shoulder
pain and disability across the lifespan of competitive swimmers.

Tate A, Turner GN, Knab SE,
Jorgensen C, Strittmatter A, Michener LA.
J Athl Train. 2012;47(2):149-58.
https://www.ncbi.nlm.nih.gov/pubmed/22488280 (Full text is available for free)

Swimming is a sport that is
commonly associated with shoulder injury and pain.  Similar to other overhead sports there are
anatomic and biomechanical adaptations that occur but in swimming it is often
more difficult to detect due to swimming being a bilateral sport.  In addition, it is still unknown which of the
adaptations are linked to shoulder pain and disability which makes creating
injury prevention programs difficult.  Therefore,
the purpose of the study was to determine if swimmers with shoulder pain (in 4
age groups; 8-11 years, 12-14 years, 15-19 years, and masters) had different
physical characteristics, training methods, or swimming exposures compared to
swimmers without shoulder pain.  The
study included 236 female swimmers ranging in age from 8 to 77 years old.  The swimmers completed three questionnaires
to determine their swimming exposure, shoulder pain and dissatisfaction (
shoulder score
), and shoulder function (Disabilities
of the Arm, Shoulder and Hand; DASH)
.  In
addition, the authors measured several physical characteristics, which included
passive shoulder range of motion (ROM), shoulder strength, pectoral muscle
length, core endurance, and scapular dyskinesis.  For shoulder ROM, they assessed internal and
external rotation at 90° of abduction, flexion (with the elbow maximally
flexed) for triceps tightness, and flexion (with shoulder external rotation) for
latissimus dorsi tightness.  For
strength, the authors assessed internal and external rotation at 90° of
abduction, horizontal abduction, shoulder elevation, serratus anterior, lower
and middle trapezius.  Pectoral muscle
length was measured at rest and on stretch at 90° of abduction.  Core muscle endurance was assessed with the
side bridge
.  One examiner assessed scapular
dyskinesis visually with a grading scale of normal, subtle, or obvious dyskinesis
(winging or abnormal movement) with weighted shoulder flexion and
abduction.  They found that young
swimmers (under 12 years old) had shoulder pain; however, older swimmers had
pain, dissatisfaction, and disability. 
High school swimmers had the most reported exposure and shoulder
symptoms.  Exposure and previous injury
was found to be associated with shoulder pain in the high school and masters
groups.  Participation in another sport
was associated with less shoulder pain. 
The young symptomatic swimmers (under 12 years old) were found to have
reduced shoulder ROM (flexion and latissimus dorsi tightness), muscle weakness
(middle trapezius and internal rotation). 
While the 12 years or older symptomatic swimmers had reduced pectoral
muscle length and decreased core endurance. 

This is the first study of its
kind in swimming and I commend the authors on an extremely great job of
providing a complete examination of swimmers.  Examining a large amount of physical
characteristics in swimmers across the lifespan will allow clinicians to identify
the adaptations that develop in swimmers in the presence of pain.  To identify true risk factors longitudinal
studies are required.  However, similar
to studies in baseball, the authors found that exposure was related to shoulder
pain.  Baseball has recently adopted
pitch limits in youth leagues; however, swimmers have no such regulations in
place.  Swimmers often practice twice a
day and 5 to 6 days a week.  Clearly this
amount of repetition may be problematic and may need to be addressed in
swimming.  Several physical
characteristics were found to be associated with shoulder pain.  Shoulder flexibility and pectoral muscle
length are were associated with shoulder pain and are easy to address by implementing
stretching programs to address these negative adaptations.  The question still remains at what point do
these athletes have too much flexibility? 
In addition, muscle strength and endurance seem to be problematic.  Again, these factors are easily corrected in
prevention programs.  Imbalances at the
shoulder and core can weaken the kinetic chain and therefore cause
compensations or increased amounts of stress on certain tissues.  Do you see similar adaptations in your
swimmers?  Do you perform a preseason
screen on your swimmers to identify these adaptations?

Written by: Stephen Thomas
Reviewed by: Jeffrey Driban

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Tate A, Turner GN, Knab SE, Jorgensen C, Strittmatter A, & Michener LA (2012). Risk factors associated with shoulder pain and disability across the lifespan of competitive swimmers. Journal of athletic training, 47 (2), 149-58 PMID: 22488280