Flexibility of internal and external glenohumeral rotation of junior female tennis players and its correlation with performance ranking.
Ching-Cheng Chiang, Chih-Chia Hsu, Jinn-Yen Chiang and 2 others
PMID 28174438WHAT IT FOUND
Junior female tennis players had less internal rotation in the dominant shoulder than the other side.
More internal rotation in both shoulders was linked to better year-end ranking.
Key findings
01Internal rotation averaged 59.2 ± 10.0 degrees on the dominant shoulder and 64.0 ± 11.7 degrees on the nondominant shoulder, and only internal rotation differed significantly between shoulders.
02Year-end ranking was significantly correlated with internal rotation of the dominant shoulder (r = -0.552) and internal rotation of the nondominant shoulder (r = -0.588).
03Ranking was not significantly correlated with age, height, weight, or BMI.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample was small and limited to female junior tennis players, so it may not apply to male players, adults, or other sports. The design measured shoulder rotation and ranking at one time and cannot show that less rotation caused poorer ranking. Participants were free of severe upper extremity injury in the three months before measurement, so it is unclear how injured or painful shoulders behave. Ranking depends on many factors beyond shoulder flexibility.
Declared interests
No conflicts of interest or funding were reported in the supplied text.
The easy way to misread this
Do not conclude that less internal rotation causes worse ranking. The study measured shoulder rotation and ranking at one time and did not test any intervention.