Intersession reliability and magnitude of change of isokinetic testing of the glenohumeral rotators in overhead athletes with unilateral shoulder anterior instability

To investigate the reliability and magnitude of change of isokinetic testing of the glenohumeral rotators in overhead athletes with unilateral anterior shoulder instability. Test-Retest Clinical Thirty patients (17 males, 27.9±10.8 years) with unilateral anterior shoulder instability. Maximal and average peak torques (PTa), and total work values were extracted from shoulder internal and external rotation in concentric and eccentric modes at 60°/s, and in concentric mode at 180°/s. PTa at 60°/s presented the highest reliability [Intraclass Coefficient of Correlation (ICC): 0.88 to 0.95] and lowest measurement error Minimal Detectable Change at 95% confidence interval (MDC 95% ): 23.2 to 35.4%], irrespective of the movement direction and contraction modalities. Conventional, functional and modal ratios based on these average values displayed poor-to-good reliability [ICC: 0.16 to 0.88] and high measurement error [MDC 95% : 22.6 to 43.2%]. Despite significant differences (p