Shoulder functional ratio in elite junior tennis players.
OBJECTIVE
To evaluate shoulder rotation strength and compare the functional ratio between shoulders of elite junior tennis players.


METHODS
This cross-sectional study evaluated muscular rotation performance of 40 junior tennis players (26 male and 14 female) with an isokinetic dynamometer.


METHODS
Strength variables of external (ER) and internal rotators (IR) in concentric and eccentric modes were considered. For the peak torque functional ratio, the eccentric strength of the ER and the concentric strength of the IR were calculated.


RESULTS
All variables related to IR were significantly higher on the dominant compared to the non-dominant side in males and females (p<0.05), but only boys exhibited this dominance effect in ER (p<0.05 and p<0.001). Regarding functional ratios, they were significantly lower for the dominant shoulder (p<0.001) and below 1.00 for both groups, indicating that the eccentric strength of the ER was not greater than the concentric strength of the IR.


CONCLUSIONS
Elite junior tennis players without shoulder injury have shoulder rotation muscle strength imbalances that alter the normal functional ratio between rotator cuff muscles. Although these differences do not seem to affect the athletic performance, detection and prevention with exercise programs at an early age are recommended.
NEO-Orthopedic Sports Medicine Research Center, Rua Botucatu, 591, cj 114, Vila Clementino, São Paulo, SP, Brazil. michelefs@uol.com.br
Michele Forgiarini
MF
Saccol
Guilherme Conforto
GC
Gracitelli
Rogério Teixeira
RT
da Silva
Cristiano Frota de Souza
CF
Laurino
Anna Maria
AM
Fleury
Marília dos Santos
Mdos S
Andrade
Antonio Carlos
AC
da Silva
D000293:Adolescent; D000367:Age Factors; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D017006:Rotator Cuff / Q000502:physiology*; D012737:Sex Factors; D012782:Shoulder / Q000502:physiology*; D012785:Shoulder Joint / Q000502:physiology*; D013715:Tennis / Q000502:physiology*; D019415:Torque