Power as a parameter in the functional assessment of knee flexions and knee extensions on weight stack machines

Abstract The study investigates the reliability of novel knee extension and knee flexion tests and their sensitivity in discriminating between-group and between-leg differences. Subjects performed maximal effort single reps of knee extension and knee flexion exercises with stepwise increasing weights up to 1RM, and a set of 15 repetitions at the previously established weight at which maximal power was achieved. Mean power during knee extension and knee flexion exercises was found to be a reliable and sensitive parameter able to discriminate between different physical activity level groups. It is also a sensitive parameter for the assessment of the differences in an individual between the injured and non-injured legs. Also, the fatigue index is a sensitive measure of the muscular endurance of both knee extensors and knee flexors. It may be used for the screening of individuals with sedentary lifestyle and for those conducting post-rehabilitation exercise programs following a lower limb injury.