The purpose of this study was to compare the effect of two different positions of shoulder internal rotation (IR) and external rotation (ER) on isokinetic concentric and eccentric peak torque as well as conventional and dynamic ratios. Nineteen athletes (Eigth judo and eleven tennis players), (20.3 ± 5.2 yrs) performed 5 maximal unilateral isokinetic concentric shoulder IR and ER repetitions at 60°/s and 120°/s. The subjects also performed 3 and 5 maximal eccentric shoulder ER repetitions at 60°/s and 120°/s respectively. The tests were performed in two seated positions: 1) with the shoulder abducted in the scapular plane, and 2) with the shoulder flexed in the saggital plane. Shoulder dynamic control ratio (DCR) and conventional ratio were also assessed. The scapular plane position showed significantly (p < 0.05) greater peak torque (PT) values than the saggital plane position during concentric IR at both speeds. However, the saggital plane position PT values were significantly greater during concentric and eccentric ER in both speeds. Additionally, the DCR and the conventional ratio values were significantly greater for the saggital plane shoulder position. These results suggest that test position is an important control variable in isokinetic shoulder IR and ER testing.