This file was dowloaded from the institutional repository Brage NIH -brage.bibsys.no/nih Johnsen, M. B., Eitzen, I., Moksnes, H., Risberg, M. A. (2013 Methods: Twenty-eight sports active children (12.4 ± 0.3 years old) were tested three times in two test sessions separated by one week. They performed four single-legged hop tests and concentric isokinetic torque measurements during knee extension and flexion. Inter-and intrarater reliability were calculated using the intraclass correlation coefficient, (ICC 2,1). Relative terms of the standard error of measurement (SEM%) and smallest real difference (SRD%) were emphasized to allow comparison between the different variables.Results: Twenty-six children were included for statistical analysis. ICCs for inter-and intrarater reliability were moderate to high for the hop tests (0.62 to 0.91) and isokinetic measurements (0.76 to 0.87). SEMs% were low for the hop tests (3.9% to 7.4%) and the isokinetic measurements (5.2% to 8.9%). SRDs% were 20.5% or less for the hop tests, 15.7% or less for knee extension and 24.6% or less for knee flexion.
Conclusion:The single-legged hop tests and isokinetic muscle torque measurements demonstrated moderate to high reliability with low measurement error in sports active children. A change above 20.5% for the singlelegged hop tests, 15.7% for knee extension, and 24.6% for knee flexion is necessary to represent a real change in knee function.Level of Evidence III.