Ergonomics is the science concerned with fitting the job or task to the physical and mental capabilities of the worker.

Applying ergonomics principles to the workplace can reduce fatalities, injuries and health disorders, as well as improve productivity and quality of work.

Poor ergonomics can lead to the following hazards:

Under the Occupational Health and Safety Act, Ministry of Labour, Training and Skills Development inspectors check to see if these hazards in the workplace are addressed.

Musculoskeletal disorder hazards

Musculoskeletal disorder or MSD is an umbrella term for a number of injuries and disorders of the musculoskeletal system, including:

  • muscles
  • tendons
  • nerves
  • bursa
  • blood vessels
  • joints
  • spinal discs
  • ligaments

Some other terms that mean the same as MSD, include:

  • repetitive strain injury (RSI)
  • cumulative trauma disorder
  • work-related musculoskeletal disorder
  • musculoskeletal injury (MSI)
  • occupational overuse syndrome

MSDs may occur when the demands of the job exceed the capabilities of the person doing the job.

To prevent MSDs, it's important to apply good ergonomics principles.


MSDs can occur suddenly or develop gradually over weeks, months or even years. They are linked to known hazards in the workplace. The key hazards, which can act in combination, are:

  • force
  • fixed or awkward postures
  • repetition

Other MSD hazards include:

MSDs do not include injuries or disorders that are the direct result of:

  • a fall
  • being struck by or against objects
  • being caught in or on objects
  • a vehicle collision
  • acts of violence


MSDs are the number one type of lost-time work injury reported to the Workplace Safety and Insurance Board in Ontario.


  • cause pain and suffering for thousands of workers every year
  • cost Ontario's workplaces hundreds of millions of dollars due to worker absence and lost productivity

Employers can also face indirect costs when a worker has suffered from an MSD, including:

  • overtime or replacement wages
  • workstation and equipment modifications
  • administration
  • training costs for replacement workers
  • lost productivity
  • reduced quality

Common activities that lead to MSDs

Manual material handling tasks

Manual material handling, which includes the manual lifting, lowering, pushing, pulling or carrying of objects, is a common task for workers in many workplaces.

Manual handling can expose workers to hazards resulting in MSDs. Good ergonomics design of manual handling activities prevents these types of injuries.

To learn more:

Client handling activities

Client handling refers to activities such as lifting, transferring and repositioning a client, patient or resident. This commonly occurs in the health care sector.

MSDs are the most prevalent injury among health care workers. Half of these are due to client handling activities.

To learn more about client handling:

Working at a computer

People working on computers for prolonged periods are at increased risk of developing a number of health problems. These include:

  • headaches
  • back pain
  • upper limb MSDs (for example, carpal tunnel syndrome)
  • visual fatigue (for example, eyes become irritated and uncomfortable, headaches, blurred vision)

The risk of computer-related health problems can be reduced by:

  • proper lighting
  • good task design
  • appropriate work station design (for example, suitable desks and adjustable chairs)
  • the use of suitable equipment (for example, keyboards, mouse and monitors)

Learn more about computer ergonomics.

Benefits of having a prevention program

Preventing injuries is less expensive than making changes and corrections after an injury has occurred.

With an MSD prevention program, the workplace gains:

  • healthy workers who are free from discomfort and can perform their jobs more efficiently
  • reduced:
    • WSIB lost-time injury claims and the associated costs
    • administrative costs related to claims management and investigations
  • improved:
    • ability to retain experienced, knowledgeable and skilled workers
    • employee satisfaction, morale and well-being
    • process for bringing workers back to work after they have been injured
    • quality, productivity and profits

Visibility hazards

Ergonomics can reduce the visibility hazards that can lead to a worker being struck by a vehicle or mobile equipment.

Generally, these incidents occur when the operator of a vehicle or mobile equipment:

  • cannot see a worker
  • doesn't notice a worker even though they were in their line of sight

Some factors that can affect an operator being able to see a worker include:

  • their line of sight is blocked by:
    • some part of the vehicle or mobile equipment
    • loads that are being carried
    • the environment (such as stacks of materials, structural columns, etc.)
  • there is low lighting or glare
  • the worker is not wearing appropriate high visibility clothing
  • there is not enough contrast between the worker and the background

Some factors that can affect an operator noticing a worker include:

  • they do not expect the presence of workers
  • their visual and cognitive workload is too great (for example, the operator is being required to do too many things at the same time)
  • the worker is in their peripheral vision

Learn more about visibility hazards at industrial workplaces and mining workplaces.

Fall hazards

Ergonomics can protect workers from slipping, tripping and falling or falling from a height (for example, when using a ladder).

The task the worker is doing, their posture and how much force they are exerting play a major role in causing a fall.

Factors that can influence balance and the risk of a fall include:

  • body size and stature
  • postures assumed
  • points of contact
  • forces and loads applied
  • the size of the base of the support

Work should be designed so that a worker can continuously maintain their balance when working from a ladder and climbing up and down.

Learn more about ladder ergonomics with the following resources:

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations, and should not be used as or considered legal advice. Health and safety inspectors apply the law based on the facts in the workplace.