Development, application, and reliability of methods for ergonomic workload assessments in production evaluation and workstation design
Licentiate thesis, 2021

Ergonomics assessments of conditions for humans at workstations and in manufacturing processes are necessary to prevent work-related musculoskeletal disorders and enhance efficiency and quality. Many methods can be used for this from systematic observations to direct measurements and simulation. Investigations of the accuracy and reliability of many methods as well as comparisons between them have been performed, but there is still need for further work as well as development of new methods.

The inter- and intra-rater reliability of the OCRA checklist was studied through eleven ergonomists’ risk-assessments of ten video-recorded work tasks on two occasions. The statistical analysis included several parameters of reliability of which Cohen's linearly weighted kappa was the primary measure. The inter-rater agreement of the OCRA checklist was 39%, and the weighted kappa was 0.43; the intra-rater dittos were 45% and 0.52. This indicated that the OCRA checklist is a moderately reliable tool.

A risk assessment approach for digital human modelling (DHM) was developed. The approach included a reference database of epidemiological relationships between directly measured exposure and related musculoskeletal disorders. For illustration, a case in manual assembly was simulated; exposures were calculated and compared to the reference data to indicate the risk of WMSDs. The application and detailed assessment would be helpful to prioritise among different design solutions.

A 3D digital prototype laparoscopic robotic console was ergonomically evaluated using the DHM tool IMMA with 12 manikins representing anthropometries of the Swedish and US population. Work-ranges of the console and the manikins were calculated, compared and
ergonomically assessed using the Swedish standards and a US checklist for computer work. The assessment criteria related to the adjustable ranges of the screen height, height of the armrest, adjustable range of the pedals were not fulfilled. The DHM tool IMMA provides the possibility for a pre-production assessment of static work tasks.

Work-related Musculoskeletal Disorders

Risk assessment

Direct measurement

Biomechanical Exposure

Systematic Observation

Digital Human Modelling


Workplace Design



Seminariet kommer att hållas digitalt via Zoom
Opponent: Anna Brolin, Ph.D., Senior Lecturer in Integrated Product Development, University of Skövde, Sweden


Ida-Märta Rhen

Chalmers, Industrial and Materials Science, Production Systems

Ergonomic Evaluation of a Prototype Console for Robotic Surgeries via Simulations with Digital Human Manikins

Proceedings of the 20th Congress of the International Ergonomics Association (IEA 2018) Volume V: Human Simulation and Virtual Environments, Work With Computing Systems (WWCS), Process Control,; Vol. 822(2019)p. 351-363

Paper in proceeding

Ergonomic risk assessment in DHM tools employing motion data - exposure calculation and comparison to epidemiological reference data

International Journal of Human Factors Modelling and Simulation,; Vol. 6(2018)

Journal article

Intelligently moving manikin - IMMA

Swedish Foundation for Strategic Research (SSF) (PV08.000.2), 2009-06-30 -- 2013-12-31.

Subject Categories

Production Engineering, Human Work Science and Ergonomics

Medical Laboratory and Measurements Technologies

Environmental Health and Occupational Health

Areas of Advance


Health Engineering

Driving Forces

Innovation and entrepreneurship



Seminariet kommer att hållas digitalt via Zoom


Opponent: Anna Brolin, Ph.D., Senior Lecturer in Integrated Product Development, University of Skövde, Sweden

More information

Latest update

8/5/2021 6