¹National Research Centre for the Working Environment, Copenhagen, Denmark

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Introduction: Job rotation is a strategy used to prevent work-related musculoskeletal disorders (WMSDs), allowing employees to alternate between tasks with differing physical exposures. The purpose of job rotation is to distribute physical loads more evenly throughout the workday, achieving a better balance between strain and recovery, and thereby, reducing the risk of WMSDs.

For job rotation to be effective there must be sufficient variation – referred to as task diversity – in physical exposure between tasks. Assessing this diversity is crucial to understanding the preventive potential of job rotation within specific work environments.

The aim of this study was to develop a novel exposure score that integrates electromyography (EMG) and kinematic data into a single, interpretable metric for evaluating task rotation. The score quantifies the overall physical exposure associated with specific work tasks by capturing both muscular and movement-related demands. The score was developed within a larger project to map the physical exposure at selected workstations and, through this, provide practically applicable insights into job rotation for slaughterhouse workers in Denmark.

Methods: Sixteen slaughterhouse workers were individually equipped with sensors to measure muscle activity (EMG) and movement (Xsens). Prior to data collection, participants completed maximal voluntary contractions. Recordings were conducted at 12 different workstations along the production line, with randomized starting positions. At each workstation, approximately six minutes of work were recorded.

Based on these measurements, the exposure score was developed to provide a comprehensive assessment of physical exposure for each task. The score incorporates data on muscular load, posture, and movement dynamics from key body regions including the trunk, shoulders, neck, elbows, and wrists. It also accounts for time spent in specific postures and movement velocity – particularly the angular velocity of the shoulders and wrists.

Results: The exposure score successfully detected differences in physical exposure between workstations i.e. task diversity in physical exposures, indicating its potential to integrate multiple exposure measurements when evaluating and comparing task demands. By identifying tasks with contrasting physical, the score can/may support the design of job rotation schedules with the potential to enhance variation and reduce the risk of WMSDs.