English title: Fatigue in forest work.
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.