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

Developing a personalized decision-making tool to minimize handling risks associated with symmetrical and asymmetrical postures


Excessive lumbar loads are a significant risk factor in back pain. Biomechanical modelling of the spine is the only non-invasive procedure for estimating such loads, but the complexity of the models restricts their use by ergonomists.
There are a number of tools to help ergonomists identify situations presenting a potential risk of back injury and limit the load on the lumbar spine. These tools do not calculate the lumbar load directly, but instead provide an estimate of the maximum weights a worker can safely lift.

New regression equations were recently developed based on the detailed kinetics model of Shirazi-Adl’s group. These equations are, however, limted to symmetrical postures and do not take account of variations in worker weight and height.

The purpose of this project is to develop predictive equations for spinal loads, taking account for the first time of personal factors such as individual weight and height. It also aims to improve predictive equations for spinal loads in asymmetrical handling tasks. These equations would be used by ergonomists to assess situations carrying a risk of injury. The researchers also wish to propose adjustments to the NIOSH (National Institute for Occupational Safety and Health) lifting equation and compare the estimates against those of other tools.

Additional Information

Type: Project
Number: 2014-0009
Status: Completed
Year of completion: 2020
  • Aboulfazl Shirazi-Adl (Polytechnique Montréal)
  • André Plamondon (IRSST)
  • Navid Arjmand (IRSST)