Inter-session Reliability of Isokinetic Strength Testing in Knee and Elbow Extension and Flexion Using the BTE PrimusRS.

CONTEXT The use of isokinetic dynamometers playing an important role in different settings of sports and medicine. Therefore, a high reliability of these devices is required. OBJECTIVE The aim of this study was to examine the inter-session reliability of the dynamometer BTE PrimusRS regarding to the isolated single-joint exercises extension / flexion of the knee and elbow for isokinetic testing. DESIGN Inter-session reliability. SETTING Clinical settings and sports science. PARTICIPANTS 16 young male students. INTERVENTION The testing protocol includes five consecutive repetitions (concentric/concentric) at a velocity of 60° per second for the exercises. MAIN OUTCOME MEASURES Raw data of torque curves were used to determine the peak torque (PT). Reliability was evaluated with the intra-class correlation coefficient (ICC), the limits of agreement (LoA), the bias and the variability of measurements (V) of various evaluation methods of the peak torque, where raw and smoothed data were analyzed. RESULTS We found high ICC values (0.954 - 0.991) for the used exercises. However, the LoAs yielded up to over 16 Nm and the V yielded up to nearly 9 % in several testing exercises indicating poor absolute reliability. CONCLUSION The BTE PrimusRS shows good to excellent reliability. However, regarding the absolute measures of reliability, the users must decide as experts in their fields whether this reliability is sufficient for their purposes.