Ph.D. Defence by Mikkel Brandt Petersen
Mikkel Brandt Petersen will defend his Ph.D. thesis on: "Participatory ergonomics intervention with technical measurements in the construction industry: cluster randomized controlled trial - Including development of a new method for measuring physical workload"
15.06.2018 kl. 13.00 - 17.00
Work-related musculoskeletal disorders (WMSD) are among the most prevalent health problems in the industrial countries and have extensive consequences for individuals and society in terms of work disability and sickness absence. Worldwide, low back pain causes more disability than any other condition. Heavy lifting, working in awkward postures, pushing and pulling and manual material handling – which frequently occur during construction work - are associated with increased risk of developing WMSD. Recent data from the Danish Work Environment & Health questionnaire study show that construction workers have a higher degree of; heavy lifting, pushing and pulling, and work with back rotation or forward bending than the general working population. The number of high-quality intervention studies aiming at reducing the workload in the construction industry is scarce, and the methods for evaluating workload have often been based on selfreports. Technological development has made it possible to obtain technical measurements during full working days by using surface electromyography (sEMG), kinematics (IMU), heart rate and video recordings. However, these measurements have not previously been used simultaneously and in a synchronized manner to detect events of excessive workload during a full day of construction work. While technical measurements are important for achieving good measurements of exposure, making actual changes at the workplaces in the construction industry can be difficult. Participant involve-ment in interventions has previously shown promising results in certain job groups and may help to fit the intervention to the context, culture, as well as the psychosocial and organizational conditions on the working site. However, whether participatory ergonomics can reduce the physical workload in the construction industry is unknown. The overall aim of this PhD-thesis was to investigate whether a participatory ergonomics intervention with technical measurements consisting of IMU sensors, sEMG, heart rate and video recordings of physical workload can reduce the number of events with excessive physical workload during a working day in the con-struction industry. A Study protocol that described the purpose and methods planned to be used in the intervention was published (Study I). Two methodological studies (Study II and III) were conducted with the purpose of developing a reliable and accurate method to detect events of excessive physical workload during construction work. In Study II the interday reliability of sEMG of the back and neck muscles was tested during standardized lifting situations, which shoved moderate to almost perfect reliability (ICC3.k) for 89% and 73% of the lifting situations, for absolute and normalized values, respectively. In Study III the accuracy of detecting high or low-risk lifting during standardized lifting situations were tested and showed accuracy up to 78.1%. Based on the results from Study II and III a cluster randomized controlled trial with technical measurements, i.e. sEMG, IMU sensors, heart rate, and video recordings, obtained simultaneously at baseline, three and six months follow-up, was conducted in the Danish construction industry (Study IV). The sEMG and IMU sensors were used to detect events of excessive physical workload. The video recordings showing excessive physical workload for the construction gang in question were used in a participatory ergonomics intervention involving construction workers and managers. This intervention consisted of three workshops over a three month period. During the workshops several solutions to decrease the physical workload were proposed. The results of the intervention did not show an effect on the number of events of excessive physical workload. However, secondary outcome (questionnaires) showed a decrease in general fatigue after a typical working day from baseline to second follow-up as well as increased influence of own work from baseline to first follow-up, in the intervention group compared with the control group. Altogether, this PhD-thesis demonstrates new reliable methods for detecting events of excessive physical workload during laboratory settings. This thesis demonstrated that it is possible to use the method for event detection in field environment despite a lack of decrease in the number of events with excessive physical workload after the intervention.
Det Nationale Forskningscenter for Arbejdsmiljø, Lersø Parkallé 105, 2100 København Ø