Acute effects of a shoulder rotators strength training session in young swimmers

Abstract

Introduction Competitive swimming usually carries large volumes of daily training, in which the propulsive force is obtained mainly by the upper limbs. Therefore, there may be an overload on the shoulder joint, which can promote muscle imbalances. Some studies showed that shoulder rotators injury prevention training programs are essential (Batalha et al., 2015), and the majority of them are performed before the swim practice. This study aims to analyse the acute effects of an injury prevention training session on shoulder rotators strength, endurance and muscle balance. Methods A group of 23 young swimmers (13.43 ± 1.38 years old; 58.97 ± 7.75 Kg; 168.61 ± 7.91 cm of height) were evaluated. The peak torques (PT) of shoulder internal (IR) and external rotators (ER) were assessed before and after one session of a compensatory strength training program. The ER/IR ratios and the fatigue index (FI) were also assessed. The measurements were obtained with concentric actions at 60º/s (3 reps) and at 180º/s (20 reps), using an isokinetic dynamometer (Biodex System 3 - Biodex Corp., Shirley, NY, USA). The T-Student test for paired samples was used to compare the results. Results Despite a decrease in the ER and IR strength values after the conducted training, there were no significant differences between pre and post assessment, on both shoulders at 60°/s. Likewise there were no statistical differences in the ER/IR ratios. At the angular speed of 180º/s in the dominant shoulder, the compensatory strength training session does not induce any significant acute effect in the same variables ER-PT (p=0.264), IR-PT (p=0.138) and ER/IR ratios (p=0.750). Also for the ER-FI and IR-FI, statistical differences weren’t observed (p=0.910 and p=0.102 respectively). Regarding the non-dominant shoulder, at the same angular velocity (180º/s), results were similar to the ones obtained in the dominant shoulder. Conclusions The realization of an injury prevention program does not have a significant acute effect on strength, endurance and muscle balance of rotators of the shoulder in young swimmers. Performing a shoulder rotators strength training program before the aquatic training it seems appropriate.