Absorption of vibration energy in the human hand and arm.

A possible basis for the risk assessment for hand-transmitted vibration may be to determine the amount of energy absorbed in the human hand and arm. In the present study, the mechanical energy absorption in the hand-arm system was measured within the frequency range of 4 to 1000 Hz. The study was carried out on ten healthy subjects during exposure to sinusoidal vibration. The influence of various experimental conditions, such as vibration direction (Xh, Yh, Zh), grip force (25-75 N), vibration level (8-45 mm/srms), and hand-arm posture were studied. The outcome shows that the energy absorption in the human hand and arm depended mainly on the frequency and direction of the vibration stimulus. Higher vibration levels, as well as firmer handgrips, resulted in higher absorption of energy. Varying hand-arm postures had only a small influence on the amount of absorbed energy, while the constitution of the hand and arm affected the energy absorption to a larger extent.