Isokinetic strength testing in older women: A comparison of two systems

Isokinetic equipment is used for measuring muscular strength for both experimental and rehabilitative purposes. In this study two LIDO® isokinetic dynamometer systems, the LIDO-digital and the LIDO-active, were compared at 60, 180, 240, and 300°/sec for peak torque (PT) and average work output (WO) of knee flexion and extension. Twenty-five elderly women (age range = 65-86) were tested on both systems within seven days. The data were compared by using a repeated measures ANOVA followed by a Dunn-Bonferroni posthoc comparison (p ≤ .0125). Knee flexion PT was significantly different (p ≤ .0125) at all angular velocities tested. Knee extension PT was significantly different (p ≤ .0125) at all speeds except 180°/sec. Knee flexion WO was significantly different p ≤ .0125) at all angular velocities except 60°/sec; whereas, knee extension WO was not significantly different. The data indicate that for healthy women over 65, these two systems are not totally comparable for knee extension and flexion. Therefore, in both clinical and experimental settings, caution should be taken when comparing results across systems or when comparing patients' results with norms established from data obtained on a different system.