Combined Effect of Vibration Intensity, Grip Temperature, Noise and Pushing Power on Grip Forces and Skin Temperatures of Fingers

Koh, Kyungsim; Griefahn, B; Fritz, M; Brode, P

Abstract

Recent studies reveal that grip forces during the hand-arm vibration are most significant for the genesis of vibration-induced white finger syndrome. Therefore, exerted grip forces and skin temperatures or fingers were regarded as dependent variables in experiments and the effects of grip temperature, noise, pushing force, vibration and the combined effect of vibration and pushing force were studied. The objectives or the present study were, first, to varify and compare the changes of grip force affected by grip temperature, noise, pushing force, vibration and the combined effect of vibration and pushing force and, second, to observe the reaction of finger skin temperature affected by above factors. Forty-six healthy male students(25.07+/-2.85) participated in five systematically permuted trials, which endured 4 minutes each other. Experiments were executed in a special chamber with an air temperature of 21 C. In each experiments, the subjects were exposed to five experiment types: (l) grip force of 25 N only, (2) pushing force of 50 N, (3) acceleration of vibration 7.1m/sec2(z-direction), (4) pink noise or 95 dB(A) and (5) combination of pushing force 50 N and acceleration of vibration 7.1m/sec2. A repeated-measures analysis of variance(ANOVA) was performed on the grip force to test whether it was affected by noise, pushing force, vibration and pushing force. The present results show that vibration was significantly related to the increase of grip force, but the other factors, such as pushing force, noise and grip temperature had no significant influence on the increase of grip force and that the reaction of finger skin temperature were significantly affected by the skin temperature at start of experiment and grip temperature, not grip force and other experimental conditions. Therefore, we suggest that the management for decreasing the grip force is meaningful to prevent the occurrence of Hand-arm vibration syndrome (HAVS).