Ergonomic evaluation on wheel-scrolling motions for reducing the risk of musculoskeletal disorders

The objective of this study is to find characteristics of wheel scrolling motions and to control such characteristics to observe whether or not subjective symptoms associated with musculoskeletal disorders were reduced. Wheel scrolling motions were obtained by a high-speed video camera and changes in joint angles and subjective evaluations for muscular loads were monitored. Susceptible characteristics of musculoskeletal disorders were enumerated by analyzing dynamic changes in finger joint angles and two mouse prototypes to reduce such characteristics were produced for evaluation. As a result, muscular loads were higher when subjects performed scroll-up motions (SU) than scroll-down motions (SD). Unnecessary finger motions with potentially awkward posture were also found during SU motions. Muscular loads during SU motions seemed related to the awkward postures of the finger. All in all, it was revealed that such awkward posture lead to the muscular loads.