Computer technology use has been toted as the modern-day saviour in the workplace, bringing with it greater access to information, automation of redundant tasks, increased productivity and better communication. For these reasons, many industries have been desperately trying to play “catch-up” (the health care industry first comes to mind) in embracing the newest information technology solutions. Far too often businesses across various industries neglect to properly consider of the negative physical aspects associated with prolonged computer use. This blog post will provide you with a very high level overview of some of the scientific literature investigating the ergonomics of human-computer interaction (HCI) in the office setting.
Computer-Related Injury in the Workplace
The overall prevalence of work related musculoskeletal injuries (MSIs) are quite high in Canada (40% in Ontario in 2010 – I am in Canada hence the Canadian context) (WSIB, 2010). A prevalence study by Sluiter and Frings-Dresen (2008) reported that about 25% of office workers in European countries suffered from neck and shoulder pain associated with computer use. Research has shown that the scientific ergonomics approach reduces the physical risks associated to prolonged computer users in office situations (Bongers, 2007; Brace, 2005; Demure et al. 2000; Lewis et al., 2001; Ketola et al., 2002; Sluiter et al., 2008). Common issues associated with prolonged computer use are hand, neck, shoulder and lower back pain, visual problems, and occasional issues with mental illness (emotional instability and depression). Since computer-related workplace injuries may lead to an increase in operating costs due to a loss in productivity (Brace, 2005), many organizations have implemented programs that specifically target the reduction and prevention of computer related MSIs. The most common method has been to conduct office ergonomics assessments, which involves the evaluation of an individual employee’s workstation by a person with specialized ergonomics training.
The Role of Office Ergonomics
When evaluating a “traditional” office workstation, involving a worker seated at a desk with desktop computer, the Eastman Kodak Company’s Ergonomic Design for People at Work ([KODAK], 2004) is the manual of choice for ergonomics professionals. In regards to HCI, the Kodak guide explains that a poor set-up of the personal workstation results in sustained awkward postures. The components for the evaluation of the computer workstation include two major body areas: neutral eye height in relation to monitor height and hand working height in relation to neutral elbow flexion angle. The worker’s individual anthropometrics are taken into consideration to ensure that any adjustments made to the workstation are optimal for that particular individual. To determine monitor position, the user is seated in a chair with their gaze looking directly forward. The monitor is positioned between 40 and 74cm away from the user. The monitor height is then adjusted so that the user’s gaze is slightly downward at about 15 degrees. This setup keeps the user’s posture and neck angle at the neutral position while using the computer. Previous research has shown that non-optimal workstation design can result in sustained non-neutral neck postures, significantly increasing the probability for a work related neck or back MSI.
A neutral hand working height for keyboard and mouse interaction has been shown to promote a neutral shoulder posture and provide forearm support (Aaras et al., 1998; Blatter & Bongers, 2002; Gerr et al.; 2006; Lassen et al., 2004;). The Kodak manual (2004) states that a work surface, which is either too high or too low, may not only have implications for wrists and forearms, but also may cause shoulder and neck discomfort. In order to achieve a neutral hand working position, the keyboard and mouse should allow for the elbow to be in its neutral position, defined as approximately 90 degrees elbow flexion when the user is in an optimal over-sitting position.
Laptops are Another Form of Evil
When working with laptop and notebook computers, research has shown that prolonged use places the user at a greater risk of MSI. Laptop computer use has been found to cause the user to experience significant increases in neck flexion and extension, head tilt, reductions in range of motion of the neck and shoulders and wrist problems (Astundi et al., 2010; Astundi et al., 2012; Sommerich et al., 2002; Szeto & Lee, 2002). Astundi (2012) states that most ergonomic professionals suggest using a laptop in the same workspace configuration as stated in the Kodak manual. That is, by placing the laptop screen to allow for a neutral eye position and then using an external keyboard and mouse to accomplish a neutral hand working height. As with the mobile nature of notebook and laptop computers, Astundi (2010) states that while on the go, users often place the laptop or notebook computer directly on their laps, significantly lowering the computer’s position, and increasing the chance for MSI. In his 2010 research article, Astundi reported that through the use of a lapdesk (a platform which raises the laptop or notebook up off of the legs of the user), the user’s hand and eye positions are brought back to a more normal position, potentially reducing the risk of MSI.
So, in summary…
Computer use in the office comes with an associated risk. This risk can be mitigated by using sound office ergonomics approaches when considering the purchasing and set-up of office workstations. And remember, we are here to help! If you have any questions please don’t hesitate to ask us!
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