Ergonomic Risk Assessment of Firefighters-rescuers based on Heart Rate Monitoring and Myotonometric measurements of Skeletal Muscles

摘要

This research work is dedicated to occupational health problems caused by ergonomics risks. The number of occupational diseases caused by overload in the work can be referred to firefighters who have to work very intensively, especially, at extreme situations when they are working as rescuers. Firefighters-rescuers face also high psychological demands in operative tasks, therefore, they are subjected to physical and mental work interaction. Physical load were analysed by measuring heart rate. The work postures and work phases were analysed with the OWAS method. Assessments of the muscles strain and functional state (tone) were carried out using myotonometric measurements. Interaction of mental and physical load was determined using NASA-TLX method. This study showed that firefighters-rescuers work should be considered as a moderately hard work according to average metabolic energy consumption 7.5 ± 1.2 kcal/min. These results given from fire-drill tasks (walking and carrying, climbing, ascending stairs, hammering, hose rolling) was comparable with objective fire cancellation work. Several muscle tone levels were identified allowing subdivision of firefighters into different conditional categories basing on muscle tone and fatigue. The highest degree of total workload considering mental and physical load interaction was identified for several fireman's, especially, commanding officers because temporary demands, task performance, effort and frustration are taken into consideration. It was concluded that complex ergonomic analysis consisting of heart rate monitoring, assessment of compulsive working postures, determination of mental and physical load interaction, and myotonometry is appropriate to assess the work heaviness degree and can provide prognosis of work-related musculoskeletal disorders for the firefighters-rescuers under different workload conditions. These results can also be used when deciding on necessary rest time and its periodicity.