Abstract
The aim of this study was to determine the reliability of measures of concentric and eccentric extension and flexion peak moment of the knee and elbow of prepubertal boys. Twenty boys volunteered for the study. Ten performed the knee test and ten performed the elbow test. All subjects were permitted a separate day familiarisation session and were later tested on two separate occasions, exactly 1 week apart, at the same time of day and with the same test administrators. Peak moment was measured with an adapted Biodex System-3 using continuous concentric-concentric and eccentric-eccentric cycles at 30°/s and 180°/s. The reliability measures were intraclass correlation coefficient (ICC), repeatability coefficient (RC), limits of agreement (LOA) and coefficient of variation (CV). ICCs ranged from 0.55 to 0.97 and CV ranged from 4% to 15%. There was no systematic difference in peak moment between test and retest. The various indices demonstrated moderate to high reliability of peak moment measurements in this age group which compared favourably with the existing literature. The results of the study support the reliability of measures of concentric and eccentric peak moment in studies of children's strength.