Abstract
This study compared peak torque and torque steadiness during isometric lateral and medial rotations in workers with shoulder impingement syndrome (SIS) and those with no upper limb disorders. Twenty-nine female workers were evaluated. The SIS group consisted of 14 workers (36.57 ± 5.23 years) with unilateral SIS. The control group consisted of 15 healthy workers (35.53 ± 5.46 years). Three maximal voluntary isometric contractions (MVIC) of 5-s duration were performed to determine the peak torque, which was used to calculate the target torque (50% MVIC). For assessment of the torque steadiness 3 trials were performed at the target torque for 5 s each, with visual feedback. Standard deviation (SD) and coefficient of variation (CV) were measured from the steadiness trials. Peak torque, SD and CV were not different (P> 0.05) between groups neither between affected and unaffected sides of the SIS group for both rotations. It was possible to suggest that torque steadiness, during isometric medial and lateral rotations of the shoulder, is not altered in workers with SIS when compared to healthy workers, and that maintenance of regular work activities may play an important role in preservation of the steadiness in this population.