Assessment of skeletal muscle fatigue of road maintenance workers based on heart rate monitoring and myotonometry

Abstract

ObjectiveThis research work is dedicated to occupational health problems caused by ergonomic risks. The research object was road building industry, where workers have to work very intensively, have long work hours, are working in forced/constrained work postures and overstrain during the work specific parts of their bodies. The aim of this study was to evaluate the work heaviness degree and to estimate the muscle fatigue of workers after one week work cycle. The study group consisted of 10 road construction and maintenance workers and 10 pavers aged between 20 and 60 years.MethodsPhysical load were analyzed by measuring heart rate (HR), work postures (OWAS) and perceived exertion (RPE). Assessments of the muscles strain and functional state (tone) were carried out using myotonometric (MYO) measurements. The reliability of the statistical processing of heart rate monitoring and myotonometry data was determined using correlating analysis.ResultsThis study showed that that road construction and repairing works should be considered as a hard work according to average metabolic energy consumption 8.1 ± 1.5 kcal/min; paving, in its turn, was a moderately hard work according to 7.2 ± 1.1 kcal/min. Several muscle tone levels were identified allowing subdivision of workers into three conditional categories basing on muscle tone and fatigue: I – absolute muscle relaxation and ability to relax; II – a state of equilibrium, when muscles are able to adapt to the work load and are partly able to relax; and III – muscle fatigue and increased tone. It was also found out that the increase of muscle tone and fatigue mainly depend on workers physical preparedness and length of service, and less – on their age.ConclusionWe have concluded that a complex ergonomic analysis consisting of heart rate monitoring, assessment of compulsive working postures and myotonometry is appropriate to assess the work heaviness degree and can provide prognosis of occupational pathology or work-related musculoskeletal disorders for the workers under different workload conditions. These results can also be used when deciding on necessary rest time and its periodicity.

The effects of a medical hypnotherapy on clothing industry employees suffering from chronic pain

“…Assessment of the functional state of skeletal muscles and muscle fatigue was carried out using myotonometric measurements performed with MYOTON-3 device created in Estonia, the University of Tartu. Theoretical concept of MYO is described in references [ 23 , 24 ], as well as in our earlier publication describing results of the research on skeletal muscle fatigue of road maintenance workers[ 25 ]. The working principle of MYO lies in using acceleration probe to record how peripheral skeletal muscle or its part reaction to the mechanical impact (testing end mass 20 grams, duration 15 milliseconds) and the following analysis of the resulting signal.…”

Myotonometry as a tool for determination of fatigue in the upper extremities of garment industry workers

“…The values of stiffness are in the range of 150 N/m to 300 N/m, depending on the type of the muscle. The results of "myotonometric" measurement of workers in different occupations can be found in [6][7][8]. The aim of the study is to determine the fatigue of muscles during the work process in the garment industry.…”

Effects of low-frequency electrical stimulation on cumulative fatigue and muscle tone of the erector spinae

“…An increase in muscle tone indicates an abnormal state in the musculoskeletal system and it is used as an indicator of muscle fatigue 20 ) . Roja et al reported that with additional lifting and lowering of heavy goods, muscle tone of workers increased further, whereas workers without such repetitive work showed relatively less muscle tone 21 ) . In addition, muscle tone was shown to correlate with EMG frequency and a decrease in muscle fatigue increases muscle tone as well 22 ) .…”