Articles by Erkki Wuolijoki
Category : Article
The paper deals mainly with the effects of jolting of forest tractors and processors on the health and working capacity of the driver. The literature surveyed presents especially the following points of interest: Jolting of the machine may hamper the focusing of the eyes and mastery of the controls. Long-term exposure to jolting may result in reduced sympathetic nervous activity at rest, and may impair an already existing back problem. Workers exposed to vibration, get more frequently gastric changes and changes in reproductive functions than usual. Jolting, as also the other negative physical factors of working environment, must be minimized as early as possible during the design of the machines.
The PDF includes a summary in English.
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Wuolijoki,
E-mail:
ew@mm.unknown
Category : Article
The aim of the study was to search for differences in ergonomic effects between lateral 1, 2, 3 and 4 Hz whole-body vibrations of the forest tractor driver. Healthy male volunteers, both professional drivers and students, were exposed to 692 different vibrations in four different experiments, total number of subjects being 34.
Increase of vibration displacement affected clearly the subjects’ manipulating ability. The subjective magnitude rating of vibration correlated with energy content of vibration, but no correlation was found between subjective rating and heart rate, blood pressure or urinary catecholamine excretion, although the last variables mentioned indicate the energy consumption of the body. The professional drivers rated the vibration with smaller ratings than amateur drivers.
Frequency alteration of tractor vibration can be a possibility for reduction of vibrational effects as a tool for industrial hygiene.
The PDF includes a summary in Finnish.
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Wuolijoki,
E-mail:
ew@mm.unknown
The aim of the study was to search for measurement methods of muscle fatigue in forest work. Lactic acid concentration of capillary blood was measured from test persons after submaximal and maximal strain tests in laboratory and during forest work. At rest the lactic acid content was affected mainly by the body dimensions and blood pressure. In a maximal strain test it was affected mainly by the age. In submaximal forest work lactic acid content concentrated below the attitude factor indicating working pace and below the body dimensions so that bigger persons had a higher lactic acid concentration than smaller persons.
The PDF includes a summary in English.
-
Wuolijoki,
E-mail:
ew@mm.unknown
