Reducing work-related physical stresses to prevent MSDs

In brief

  • Workplace programs that aim to reduce stresses on the body – also known as mechanical exposure – are one way to prevent and reduce musculoskeletal disorders (MSDs), or soft-tissue injuries.
  • In this study, a work line redesign resulted in substantial reductions in mechanical exposure and a reduction in MSD burden. The changes involving ergonomic change teams, which took place at two other sites, generally produced lower-intensity changes.

Why was this study done?

Preventing and reducing musculoskeletal disorders (MSDs), or soft-tissue injuries can decrease worker disability and associated costs. One way to reduce MSDs is to implement workplace programs that aim to reduce stresses on the body, of which mechanical exposures are one important group. This study explores how much change in the intensity of mechanical exposure is needed to result in reductions in MSD burden.

How was the study done?

Researchers examined three worksite ergonomic interventions that aimed to reduce mechanical exposure. Sites 1 and 2 were at the same automotive supplier. Site 3 was a courier company. The researchers looked at several factors, which included: reducing mechanical exposure in particular tasks, reducing the duration of exposure, and increasing the number of workers who had changes in their tasks.

What did the researchers find?

For site 1, employees rated the revised work line as “substantially” better than the original line. Among the findings were that mechanical exposure and task exposure decreased by 25 per cent.

At sites 2 and 3, ergonomics change teams implemented multiple changes. Workers rated the changes as positive. However, with more detailed biomechanical evaluation, it was found that although the changes reduced MSD risk factors, the changes were not sufficient to result in large reductions in mechanical exposure.

What are some strengths and weaknesses of the study?

For all sites, the task, equipment or the changes suggested were in keeping with good practice in ergonomic interventions, as the risk factors were identified and changes were implemented to eliminate or reduce the risks. One challenge remains in that it is difficult and resource-intensive to evaluate changes in mechanical exposure due to an ergonomic intervention.

Publication Information


Characterizing the intensity of changes made to reduce mechanical exposure


Wells R, Laing A, Cole D


Work, 2009: vol. 34, no. 2, pp. 179-193