Analysis of postural strain of loggers during timber harvesting in a spruce stand

Abstract

Motor-manual felling is the most common way of timber harvesting in Poland. This method of working exposes chainsaw operators to high ergonomic risk factors. One of the most significant of these is forced working postures. Research was carried out on two loggers working in a felling-age spruce stand. Over two consecutive days, video documentation was made, which was then analyzed using a computerized version of the OWAS method – WinOWAS. Based on 874 observations (467 for logger 1 and 407 f or logger 2) the positions occurring were assigned respectively to 40 and 33 different codes. The codes most frequently recorded were 2121, 2131, 4131, 1171, 4121 and 1121. Positions in categories III and IV occupied 32.5% of the working shift in the case of logger 1,and 27.3% in the case of logger 2. Static strain for both loggers was found to be average. The loggers worked most of the time with their backs bent forward. This back position was most common during felling (79.7% for logger 1, 62.6% for logger 2). Working position showed more variation in the case of the legs. Acceptable positions, such as standing on straight legs, accounted for more than 40% of all leg positions.