Current issue: 54(2)
Under compilation: 54(3)
Four teams of two workers were time-studied in clearcutting of a cypress plantation and three teams in sulky skidding. The heart rate was recorded every 30 s. The average heartrate in timber cutting was 117.5 ± 13.4 P/min, and it was mainly dependent on worker’s working capacity. Average work load index was 41 ± 3% when working at 97% performance. The production rate was then 2.5 m3/h (crew). In sulky skidding the heart rate was lower, 106 ± 1.1 P/min, as well as the work load (WLI 30 ± 1%) and performance rating (87%). The low production rate (1.1 m3/h) (crew)) over 45 m distance is mainly due to under-dimensioned load size. The energy expenditure in timber cutting was 21.4 kJ/min and in sulky skidding 16.3 kJ/min. Daily energy expenditure was 15.0 MJ/d, and most of the timber cutters belonged to the class ”exceptionally active”.
The PDF includes an abstract in Finnish.
The influence of horizontal whole-body vibration of fairly low intensity alone and combined with the mental load and motor action typical for the forest machine drive on heart rate variability (HRV), respiration rate (RR) and heart rate (HR) was studied by testing five subjects. Horizontal vibration had an influence on HR, HRV and RR. ’Control activities’ had the most influence on RR and HRV, but some influence on HR, too. ’Moving the control devices’ (motor action) gave the same response in HR as ’control activities’, but not in HRV and RR. ’Control activities’ together with ’vibration’ had a more effect on HRV and RR than these two factors singly, but not on HR. The possibilities of using these variables in field studies are discussed.
The PDF includes a summary in Finnish.