Shoulder strength profile in elite junior tennis players: horizontal adduction and abduction isokinetic evaluation

Rogerio Teixeira Silva ^1*, Guilherme Conforto Gracitelli ¹, Michele Forgiarini Saccol ¹, Cristiano F.S. Laurino ¹, Antonio C. Silva ¹ and Jefferson Luiz Braga-Silva ¹

¹ Federal University of Sao Paulo, Brazil

^* To whom correspondence should be addressed. E-mail: rgtsilva{at}uol.com.br.

Accepted 9 February 2006

Abstract

Objective To establish a normative data of muscle performance, during isokinetic horizontal abduction and adduction of the shoulder, in elite junior tennis players.

Methods A total of 36 athletes were evaluated (23 males and 13 females), with a mean age of 14 years (range - 12 to 18). For the exam we used an isokinetic dynamometer (Cybex 6000® - Ronkonkoma, NY), testing the shoulder horizontal abductors and adductors in 60 and 180 degrees per second. We reported the absolute and relative peak torque (PT and PT/BW), total work (TW), endurance ratio (ER) and the ratio of the peak torque between horizontal abductors and adductors (HAB/HAD ratio). The data were compared between dominant and non- dominant shoulder, horizontal abductor and adductor muscles and among the groups of tennis players divided by age.

Results The dominant shoulder was stronger than the non-dominant in all parameters (p<0,05), except form ER and HAB/HAD ratio. The abductors were weak in all players, when compared with the adductors (p<0,05). Also, the type of backhand (one-handed or two-handed drive) did not influence the strength of the shoulder horizontal abductors in the dominant arm. The number of years of tennis practice influenced the muscle strength in all absolute data (PT and TW), but not in the relative measurements (PT/BW and TW/BW).

Conclusion Our findings support that junior tennis players are stronger in the dominant shoulder for the horizontal abduction and adduction. The clinical relevance of the findings is not established, and more studies are needed to compare those athletes with others, and also the tennis players with non-sports individuals.

Key Words: isokinetic evaluation, shoulder, tennis, torque

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