Effects of vibration push force, exposure duration and working posture on operators performing a grinding task.

It has been shown that vibration level, push force, exposure duration and working posture cause unfavorable effects on the work performance when hand held vibrating tools are used by operators. The present study analyzed the effects of these variables on the heart rate and systolic blood pressure of the operators carrying out a manual-grinding task. Four levels of vibration (12.5, 13.6, 14.8 and 18 m/s^{2}), three levels of push force (5, 10, 15 N), three levels of working posture (180°, 150° and 120° elbow flexion) and three exposure durations of 3, 5 and 7 min were selected for the study. Thirty male subjects with no prior experience in the field of grinding participated in the study. Results indicated that in the kind of task undertaken, the main effect of equivalent level of vibration, exposure duration, push force and working posture were all statistically significant. Also an increase in the change in blood pressure and heart rate values were observed with the increase in exposure duration and push force. When the task was performed with flexion angle of 120°, change in heart rate and blood pressure values was minimum when compared with the other two working postures. Relevance to industry: Workers using various hand held tools are prone to injuries. Present research may help greatly in reducing task related injuries and enhance performance. [ABSTRACT FROM AUTHOR]