Different computer tasks affect the exposure of the upper extremity to biomechanical risk factors

Abstract

In order to determine differences in biomechanical risk factors across computer tasks, a repeated measures laboratory experiment was completed with 30 touch-typing adults (15 females and 15 males). The participants completed five different computer tasks: typing text, completing an html-based form with text fields, editing text within a document, sorting and resizing objects in a graphics task and browsing and navigating a series of intranet web pages. Electrogoniometers and inclinometers measured wrist and upper arm postures, surface electromyography measured muscle activity of four forearm muscles and three shoulder muscles and a force platform under the keyboard and force-sensing computer mouse measured applied forces. Keyboard-intensive tasks were associated with less neutral wrist postures, larger wrist velocities and accelerations and larger dynamic forearm muscle activity. Mouse-intensive tasks (graphics and intranet web page browsing) were associated with less neutral shoulder postures and less variability in forearm muscle activity. Tasks containing a mixture of mouse and keyboard use (form completion and text editing) were associated with higher shoulder muscle activity, larger range of motion and larger velocities and accelerations of the upper arm. Comparing different types of computer work demonstrates that mouse use is prevalent in most computer tasks and is associated with more constrained and non-neutral postures of the wrist and shoulder compared to keyboarding.

Association between computer use speed and age, impairments in function, and touch typing training in people with rheumatoid arthritis

“…Mouse use is a complex motor task that requires a variety of skills (19) such as high precision (pointing), rapid movements (double clicking), coordinated hand/arm movements (dragging), and superior hand/eye coordination (pointing, dragging) (20). Studies have found that elderly mouse users tend to make more errors during mouse use than younger ones (20).…”

“…Research has suggested that different mouse use tasks require different capacities (19), and therefore, mouse use training should consist of training in several skills, including accurate pointing and the ability to drag objects on a screen. Unlike keyboard use, all mouse use requires people to look at the screen while using the mouse, which may be problematic for individuals with sensory problems.…”

One-year Incidence and Risk Factors of Thoracic Spine Pain in Undergraduate Students

“…Several studies of computer users have indicated that high intensity mouse use is associated with hand/wrist and shoulder symptoms [40][41][42] . Mouse use has been found to lead to more constrained and non-neutral postures of the wrist and shoulder compared to keyboard use 43) . Thus, a plausible explanation for the association between the high percentage of mouse use and thoracic spine pain relates to less variation in working posture during mouse use, which would potentially lead to static loading of back muscles 44) .…”

Influence of Input Hardware and Work Surface Angle on Upper Limb Posture in a Hybrid Computer Workstation

“…Although a combination of these task types is required for most desktop computer use, they require different postures and physical demands. Sustained mouse use has been linked to greater wrist extension, less postural variability, and longer duration of finger force production when compared to keyboardintensive tasks (Dennerlein & Johnson, 2006b). As a result, workers who use a mouse more than 20 hr per week have a higher prevalence of carpal tunnel syndrome (Andersen et al, 2003).…”