Accuracy of measuring impedance in the hand-arm system.

In an assessment of the accuracy with which impedance can be determined in the hand-arm system, two subjects were each tested six times at 28 frequencies between 10 and 800 Hz. In addition the effect of wearing an air cushion glove was investigated, and an attempt was made to develop a simple model of the glove. The results showed agreement with other recently published data for impedance in the hand-arm system at frequencies above about 25 Hz but not below. The mean values of the impedance for a single subject had standard errors of about 10%. When the subjects wore an air cushion glove, there was only a small change in impedance, and consequently in the total amount of energy dissipated in the hand-arm system. A simple mass-spring damper model of the glove predicted that the attenuation provided by the glove was minimal, except at the highest frequencies.