Effects of grip and push forces on the acute response of the hand-arm system under vibrating conditions.

The purpose of the occupational medicine component of a joint research project was to study the effects of grip and push forces on the acute reaction of the hand-arm system under vibrating conditions. Several series of experiments were carried out by means of a vibration simulator in a laboratory environment in order to study biodynamic vibration behaviour, muscle response, skin temperature, shifts of the vibration perception threshold and the intensity of subjective vibration perception; in addition, field tests with hammer drills were conducted. On the whole, the findings obtained suggest that the coupling of the hand with the handle involved in using vibrating tools has a considerable impact on the stresses to which the hand-arm system is exposed. For this reason, future national and international rules and regulations on vibration assessment should take into consideration the effects of variations in coupling intensity.