Side dominance does not affect dynamic control strength ratios in the shoulder

Abstract

Purpose: To examine the normal strength relationship between eccentric external rotation (EccER) and concentric internal rotation (ConIR) strength ratios of the shoulder in the dominant and non-dominant extremities of healthy subjects. Methods: Fourteen men and sixteen women were tested in the scapular plane using two angular velocities: 90 and 120°/s. The dependent variables were: peak torque (PT), work per repetition (W/rep), and total work (TW) ratios. Results: The EccER: ConIR ratio in a non-athletic population was significantly greater (p < 0.05) for the dominant than the non-dominant extremities for PT, W/rep, and TW. There was no significant difference in torque production between the two-isokinetic velocities. W/rep and TW ratios were significantly higher in females than in males. Although PT was not statistically significant, a similar relationship existed (p = 0.069). Conclusion: In a healthy, non-athletic population, when tested at 90 or 120°/s, the EccER is just slight greater than its ConIR counterpart in women and men alike.