Isokinetic dynamometry on the internal rotator and adductor muscles of the swimmers’ shoulders: no differences between asymmetrical and symmetrical swimming strokes

OBJECTIVE: In this study, we compare muscular strength of the internal rotators and adductors of the shoulder between asymmetrical (backstroke and freestyle) and symmetrical (breaststroke and butterfly) swimming strokes. METHOD: We evaluated: shoulders of (a) asymmetrical swimmers (aged 21.8 ^ 3.8 years), (b) symmetrical swimmers (aged 20.3 ^ 4.5 years), (c) recreational swimmers (aged 24.5 ^ 4.5 years), and (d) control individuals (aged 25.8 ^ 3.5 years). All evaluations were performed on a Biodexw isokinetic dynamometer at velocities of 608 and 3008/second. Adduction and internal rotation movements were evaluated. The variables studied were peak torque corrected for body weight (PTQ/BW), total work (TW) and the agonist/antagonist relationship. RESULTS: There were no differences in adductor strength between the symmetrical and asymmetrical swimmers regarding PTQ/BW (symmetrical: 114.4Newto-meter vs. asymmetrical: 109.4Newton-meter) and TW (symmetrical: 642.9 Joules; asymmetrical: 641.5 Joules). There was no difference in the abduction/adduction relationship between the symmetrical (67.4%) and asymmetrical (68.3%) swimmers. There was no difference in the internal rotator musculature between the symmetrical and asymmetrical swimmers regarding the variables PTQ/BW (symmetrical 1⁄4 66.4Newton-meter and asymmetrical 1⁄4 63.4Newton-meterm) and TW (symmetrical 1⁄4 517.4 J and asymmetrical 526.7 J). There was no difference in the ratio of external to internal rotation of the shoulder between the symmetrical (65.7%) and asymmetrical (61.5%) swimmers. CONCLUSIONS: There were no differences in muscular strength in the adductor and internal rotator muscles of the shoulder between symmetrical and asymmetrical swimming strokes.