Development and assessment of a visual-aid system for reducing the risk of neck injuries for computer users

The upper-body musculoskeletal disorders, common injuries sustained by computer users, are caused by several factors. Among these, frequent and repetitive neck flexion while switching saccades between the computer screen and the keyboard is a critical cause. However, it is difficult to prevent due to the typical workstation designs. To this end, this study proposed a self-developed visual aid, aiming at reducing neck bending and flexions. To assess the effectiveness of the visual aid, which consisted of a video display program and a CCD camera, subjects were recruited to type articles in English and Chinese with and without the visual aid. Fifteen university students volunteered to participate in the first-stage study to assess the effectiveness of posture improvement, and six of them volunteered to continue on the second-stage study to assess the performance improvement after a 2-week practice. In the experiments, a posture measure system was used to measure the neck and trunk bending information. Furthermore, the duration of typing an article was also recorded. The results showed that the visual aid helped subjects reduce their neck flexion (angle and angular velocity), especially for English typing, which the subjects were unfamiliar with. Typing speed was 15–20% faster when using the ordinary typing method, compared with that using the visual aid. However, the difference in typing speed diminished after the 2-week practice. Nevertheless, using the visual aid had a strong effect on correcting typing posture. This study shows that using the visual aid can effectively improve body posture and reduce repetitive neck flexions without decreasing typing efficiency.