IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail

Impacts of work posture on muscle activation patterns during repetitive manual tasks: indicators of musculoskeletal disorders


In North America the standing position is widely used at work stations whereas in other parts of the world tasks are usually performed while seated. Extended work while standing at a station has been associated with various symptoms such as low back pain and generalized fatigue. Recent studies have also demonstrated an association between low back pain when standing for long periods and activation patterns in the muscles of the lower back and hip region. However, these patterns have never been measured for other work postures or when the standing position is accompanied by repetitive movement of the upper limbs.

In this study, the patterns of lumbopelvic muscular movements will be compared for a repetitive manual task performed in standing, sitting, and standing-sitting positions. The seat used for sitting work and the sitting/standing stool will be adjusted in accordance with ergonomic standards.

A group of workers will perform repetitive tasks according to an established protocol in their usual workplace. A peer group with no experience will do the same, but in a laboratory setting. All will work in standing, sitting, and standing-sitting position. Correlations between the discomfort scores and the muscle activation indices will be calculated for each position.

The results obtained for the two groups will be compared in order to better understand the effect of posture, experience, and the environment on the risk of musculoskeletal disorders. The collected data will be able to be used to determine the optimal postures for a given type of work station and a given type of worker (novice, experienced) performing a repetitive manual task.

Additional Information

Type: Project
Number: 2010-0063
Status: Completed
Year of completion: 2015
  • Julie Côté (Université McGill)