Ergonomic evaluation of the wood cutting task using chain saw.

Workers whose hands are regularly exposed to hand-arm vibration may suffer from damage to the tissues of the hands and arms, which cause the symptoms collectively known as hand-arm vibration syndrome. However, investigations have shown that vibration hazards can be controlled and risks might be reduced by good design of the task/tools. In the present study, an experiment was conducted for the evaluation of risk in operating chain saw. The evaluation of chain saw ergonomically performed based on four parameters--Discomfort level, EMG activity of seven different forearm muscles (ECRB, ECU, EPB, FCR, FDS, FCU and PT), angular deviation in hand-arm system and the vibration transfer to hand-arm system, while operating the chain saw on a wooden block. Ten male candidates participated for the discomfort level experiment, four participants volunteered for the EMG activity and angular deviation experiment and two participants were involved in vibration transfer recordings. The results showed that ECRB muscle was mostly affected muscle in this task of operating a chain saw. The findings also indicated that the problems were occurred due to the bad design of the rear handle of chain saw in association with the available vibration levels on hand arm system.