Characteristics of the mechanical impedance of the hand-arm system

The mechanical impedance of the human hand-arm system was measured within the frequency range of 5--1000 Hz. A handle specially designed for such measurements, was used. The studies were carried out on ten healthy male subjects during different experimental conditions defined by, three different vibration amplitudes (0.01, 0.005, and 0.001 m/s) different combinations of push (0--75 N) and grip (25--50 N) forces, and two different methods of handle mass subtraction (mathematical and electronic). The effect of test subjects' weight on the results was also studied. The outcome shows that the mechanical impedance of the hand-arm system depends on the frequency of the vibration stimuli. Impedance was found to increase rapidly with the increase of frequency starting from 80 Hz (for the 0.001 m/s vibration amplitude) and from 200Hz (for the 0.01 and 0.005 m/s amplitudes) to reach a maximum of about 950 Ns/m at 1000Hz. (Abstract shortened by UMI.)...