The Mechanical Impedance o f the Human Body in Sitting and Standing Position at

The theory of the mechanical impedance of systems with one or more degrees of freedom is applied to the human body. A method of measuring mechanical im-pedance and determining the parameters of the vibrating systems i s developed. Impedance curves for longitudinal vibrations of a sitting and standing subject are established for the frequenq range of 1 to 20 61s. The injuence of varied postitre and restraining systems is investigated. Dynamic movements of body parts are measured, direc t Zy or indirect&, and compared with the impedance curves. The responsible elemrnts in the body for the apparent resonancer are identijied. Cor-relations between the impedance function of the body and the subjective tolerance curwe to vibration are found and the reasons for the tolerance limits are eluciakted. The variability of subjecfive tolerances due to waying posture, restraining systems, cushions, duration of exposure and vibrations are discussed, and conclusions for the development of protectiue devicrs are drawn. The correlation between the steady state response of the human body system and the effects of impact is discussed