Alterations in strength of the shoulder rotators in young elite swimmers

Gustavo Antonio Meliscki,Luciana Zaranza Monteiro,Estela Cristina Carneseca,Marcos Antonio Furumoto,Everaldo Encide De Vasconcelos,Guilherme Henrique Ramos Lopes

doi:10.1590/1980-5918.030.001.ao01

Abstract

Abstract Introduction: Shoulder muscle strength imbalance is considered a risk factor for shoulder injuries in athletes, especially in sports involving arm movements above the head. Objective: To assess the strength of the external rotators (ER) and internal rotators (IR) of the shoulder in elite swimmers, to determine possible differences between the dominant and non-dominant limbs, and to calculate the shoulder IR/ER ratio. Methods: Fifteen athletes participated in the study from age 20 ± 2 years, mass of 76 ± 4 kg, stature of 1.83 ± 4 cm, and BMI of 22 ± 1 kg/m2. Duration of practice of 10.74 ± 4.03 years; training frequency 5.95 ± 0.22 days/week, 2.07 ± 0.41 hours/day; and weekly number of meters swum 34.905. An isometric dynamometer (Globus Ergo System®, Codognè, Italy) was used to assess ER and IR strength. Data were analyzed using descriptive statistics (mean and standard deviation), paired-sample t-test, Pearson’s correlation coefficient and the Statistical Package for Social Sciences software (SPSS), version 16.0. Results: IR and ER strength was lower in the left than in the right shoulder of the swimmers (p < 0.05). Additionally, ER strength ratio was higher than IR strength ratio (p < 0.05). Conclusion: The results showed that the swimmers had an alteration of the shoulder ER/IR ratio, especially in the dominant limb.

Highlights

Shoulder muscle strength imbalance is considered a risk factor for shoulder injuries in athletes, especially in sports involving arm movements above the head
Biomechanical changes caused by muscle strength imbalance between shoulder internal and external rotators may lead to an increased incidence of injuries to the shoulder of athletes [1, 9]
Since there seems to exist a relationship between low levels of unilateral shoulder proportions and potential injuries, and there are no normative data for young adult swimmers, the aim of this study was to assess the isometric performance of the shoulder external rotators (ER) and internal rotators (IR) muscles, comparing the right and the left sides, and to identify the shoulder external-to-internal rotator muscles strength (ER/IR) ratio in high-performance swimmers

Summary

Introduction

Shoulder muscle strength imbalance is considered a risk factor for shoulder injuries in athletes, especially in sports involving arm movements above the head. Studies have shown that 38% to 75% of high-performance swimmers have already had at least one episode of shoulder pain that forced them to abandon training or a competition [6, 7, 8]. Most of these injuries is associated with the athlete's shoulder IR or ER muscles, as they cover the glenohumeral joint, afford an important protection to this joint, and help improve the performance of highperformance swimmers [1]. Biomechanical changes caused by muscle strength imbalance between shoulder internal and external rotators may lead to an increased incidence of injuries to the shoulder of athletes [1, 9]

Objectives

Methods

Results