Workload when using a mouse as an input device

A newly developed mouse, which seemed to give the operator a more neutral forearm position, was compared with a traditional mouse. The muscle load was recorded by electromyography from the extensor digitorum communis, extensor carpi ulnaris, and trapezius muscles. The muscle load of the forearm was significantly less when using the new mouse compared with the traditional one. This was true for the extensor digitorum communis regarding the static (p = .0005) and the median (p = .001) values of the amplitude distribution function (ADF) and the number of periods per minute when the muscle load was below 1% of maximum voluntary contraction (p = .03). The same clear tendency was also found regarding the static muscle load from the extensor carpi ulnaris (p = .06). These results indicate the need for reducing the pronation of the forearm when working with a mouse.