The effects of body position and stabilization on isokinetic torque ratios for the shoulder rotators

Body position and stabilization is a controversial issue for shoulder rotational testing in the scapular plane. The purposes were to determine the effects of body position on the external/internal rotation (ER/IR) ratios and how closely they approximated previously reported ratios. Twenty-two healthy, informed subjects participated in test-retest isokinetic sessions involving two body positions (seated, standing), two rotational joint motions (external,internal), three velocities (60,120,180 degrees s(-1)) and two contraction types (concentric, eccentric). Intraclass correlation coefficients ranged from 0.89-0.93. A three-way ANOVA with repeated measures, used to analyze the data for contraction type separately, showed significant effects (p < 0.000) for body position regardless of body position. Concentrically, significant effects were observed for gender (p < 0.018), velocity (p < 0.000) and body position x velocity x gender (p < 0.003). It was con eluded that use of the standing position with adequate stabilization is viable and perhaps more applicable to activities of daily living. Secondly, the 'acceptable' ER/IR ratios (0.6-0.7) previously defined should be extended to 0.5-0.7 to allow for varying joint and body positioning.