There are multiple risk factors that can contribute to musculoskeletal injuries from exposure to ergonomic hazards while performing office work at home or in the office. What these risk factors all have in common is that they work to cause musculoskeletal disorders, psychosocial health effects, and reduce the quality of life outside of working hours. Risk factors come from many aspects of the workstation, task, and individual worker. They can be grouped into three main categories which are biomechanical, task-specific, and individual worker characteristics. When conducting an office ergonomic assessment for a workstation and task, the factors mentioned below are what are assessed, and controlled.

Biomechanical risk factors are present when workers perform tasks that require heavy lifting and/or excessive repetition, and awkward or static postures (1). These factors put excessive strain on the tissues of the body. Over time, the accumulated strain can result in an injury or the development of discomfort/pain. What all these factors have in common is that they remove the body from its neutral posture and loads are displaced unevenly throughout the body as a result. For excessive repetition to cause harm it does not require the lifting of heavy objects. Excessive repetition regardless of forces required to perform the movement can cause injury. One of the most common musculoskeletal disorder in the world is Carpal Tunnel Syndrome. Often this injury is associated with repetitive finger movements such as clicking and typing, in combination with compression of the wrist against a work surface. The repetitive motions result in the tissues becoming irritated and then inflamed, once inflamed the space in the carpal tunnel is reduced and the median nerve becomes compressed. The loss of sense and slight reduction in movement is a result of stress on the tissues of the wrist even though the actions require minimal amounts of force to be produced.

Task-specific risk factors include, workstation layout, high physical work, work that has high psychosocial demands, or work that requires prolonged use of visual displays. These factors are more closely associated to the requirements of the tasks being performed by the workers. Workstation layout is extremely important as it is a combination of furniture and organization of materials. A worker using a chair that has very low adjustability and support can remove the worker’s body from a neutral seated posture for extended or short and frequent periods of time. Combining a poorly suited office chair with a desk or work surface that is poorly organized can make the worker reach for items such as a mouse or keyboard. When reaching to use the mouse the worker is then in a static reaching position for a period of time which can put unhealthy stress on the tissues of the shoulder for example. Most of our working time when seated at a desk is spent using some type of visual display, being a cell phone or computer screen. Nowadays, we spend most of our time looking at a screen; without knowing the position of the screen in relation to our body plays a massive role in the risk of a musculoskeletal injury as a result of this.

Often forgotten but extremely important to consider is that workers come in all sizes. Therefore, there is hardly ever a workstation design that is a one-size fits all design. A common phrase to go by when designing a workstation or task setup is to “design it for the worker since you cannot design the worker to the workstation or task”. No two workers are the same thus when ergonomics are considered, individual worker characteristics such as smoking, a high body mass index, anthropometry, and other co-morbidities which include non-occupational related injuries are ergonomic risk factors too (1, 2). These factors are difficult to prevent from being introduced into the workspace, but their effects can be mitigated once identified. A worker’s anthropometry is an extremely important risk factor that must be considered. A workstation for a worker who is 5’2” should differ dramatically from a workstation for a worker who is 5’10”. If the workstation was designed for the taller individual in mind, the smaller worker will be required to reach or lean forward much more frequently for example. When a worker has to reach to perform their task, the risk of injury from exposure to an ergonomic hazard is significantly higher than a worker who does not have to reach to perform the same task.

This list of risk factors for exposure to ergonomic hazards is not fixed, as every situation presents other unique challenges and risks that are identified and assessed on a case-to-case basis. This is why it is extremely important to have objective and competent professionals performing ergonomic assessments.

Summary & Keywords

• Ergonomics
  • Factors in the environment that can cause damage to the musculoskeletal system.
• Objectives of Ergonomic Assessments
  • Identify risk factors
  • Quantify the risk
  • Control the risk
• Three main risk factor categories
  • Biomechanical
    • Movements the worker performs while at the workstation or completing the task.
  • Task-specific
    • Characteristics of the workstation such as organization of items and materials, and the size of the furniture.
    • Psychophysical demands of the task.
      • Highly stressful tasks can cause muscle fatigue more rapidly leading to poor postures and headaches.
    • Use of visual displays.
      • The positioning of visual displays and the characteristics of them can cause workers to lean forward to read text, constant re-focusing when looking at a screen and documents. This can lead to neck, back, and eye strains.
      • High physical work.
        • This is deceiving as a task does not require constant movement of heavy loads or the generation of high forces to be considered high physical work. 54 – 75% of a working day is spent typing, that is a lot of movements in the arm and fingers. These repetitive low force movements do pose a risk of musculoskeletal injury to workers.
  • Individual worker characteristics
    • Anthropometry and Body Mass Index
      • Workers come in all different shapes and sizes, it is important to take this into consideration when designing a workspace or task.
        • Fit the task and workspace to the worker.
    • Smoking
      • Indirectly increases your risk of musculoskeletal injury as this affects many of the systems in your body.
    • Other co-morbidities
      • Disabilities resulting from injuries that are work or non-work related. If a worker has a previous non-work related injury and this impacts the way they should be normally performing the task, most often the worker will compensate for this by altering the movements the body. This change in movements may introduce new risks that were not present before the injury and require identification and control to prevent further injury.

Questions

• How can I identify these risks in my workplace?
  • On our website www.tharris.ca we have a complementary video that walks our clients through what to look for to identify ergonomic risks at a workstation. If you are unsure always feel free to reach out to us at T.Harris Environmental Management with any questions and we will be very glad to help you with that.
• Which of these risk factors is most important?

• • All of them are very important. Each workplace will have their own unique risk factors but the main group of risk factors that is consistent throughout any workplace are the task-specific risk factors. These factors are a combination of task requirements and workstation design.
• Why are these risk factors important?

• • Most of these risk factors are work related but the effects as a result of exposure to them extend to life outside of work. Musculoskeletal injuries and other health effects that arise from ergonomic hazard exposure can seriously dampen an individual’s quality of life.
• How do I know the pain the worker is feeling is from ergonomic hazard exposure?

• • First thing you ask the worker is, “Does the pain worsen as the week goes on, and lessens on the weekend or during time off?”
    • If they say yes, then this is an indication that the pain is a result of ergonomic hazard exposure during work related tasks.
  • Second thing you ask the worker is, “Do you feel uncomfortable at your workstation or while performing this task?”
    • If they say yes, this is an indication that the workstation or task requirements remove the worker from a neutral position for long periods of time or for short frequent periods. This can eventually lead to musculoskeletal injury development.

References

1. Da Costa BR, Vieira ER. Risk factors for work-related musculoskeletal disorders: a systematic review of recent longitudinal studies. American Journal of Industrial Medicine 53: 285–323, 2010. doi: https://doi.org/10.1002/ajim.20750.
2. Klussmann A, Gebhardt H, Liebers F, Rieger MA. Musculoskeletal symptoms of the upper extremities and the neck: A cross-sectional study on prevalence and symptom-predicting factors at visual display terminal (VDT) workstations. BMC Musculoskeletal Disorders 9: 96, 2008. doi: 10.1186/1471-2474-9-96.