Clinical and ultrasonographic correlation between scapular dyskinesia and subacromial space measurement among junior elite tennis players. 
In this study, the hypothesis that tennis players with scapular dyskinesia present a smaller subacromial space than non-athletes was investigated.  Additionally, the correlation between the size of the subacromial space and abnormalities in scapular movement during arm abduction was studied.  Cross-sectional study.  A total of 53 elite tennis players and 20 control participants were enrolled in the study.  Participation was restricted to elite-level, junior tennis players who had no current shoulder pain or history of shoulder injuries.  Each individual was examined for scapular dyskinesia by a single physician and by ultrasound, with the results analysed in a blind fashion by a single radiologist.  43.4% of the tennis players and 20% of control participants presented with scapular dyskinesia.  Of the 106 shoulders evaluated, 39.6% of tennis players and 10% of control participants presented with scapular dyskinesia in the clinical examination (p = 0.005).  Ultrasonographic measurements demonstrated that tennis players presented statistically smaller subacromial spaces compared with control participants (p<0.001).  A decrease in the subacromial space was observed in tennis players when the shoulder was raised from 0 degrees to 60 degrees of abduction; however, dyskinesia-afflicted athletes demonstrated a significantly greater decrease following this movement (19.3 vs 13.8 mm, p = 0.002).  The results of this study demonstrated that tennis players with scapular dyskinesia present a smaller subacromial space than control participants.  Furthermore, when the shoulder was analysed dynamically, moving from neutral abduction to 60 degrees of elevation, the tennis players with scapular dyskinesia presented a greater reduction in the subacromial space compared with unaffected athletes.