WORKLOAD WHEN USING A MOUSE AS AN INPUT DEVICE

A newly developed mouse, which seemed to give the operator a more neut ral forearm position, was compared with a traditional mouse. The muscl e load was recorded by electromyography from the extensor digitorum co mmunis, extensor carpi ulnaris, and trapezius muscles. The muscle load of the forearm was significantly less when using the new mouse compar ed with the traditional one. This was true for the extensor digitorum communis regarding the static (p = .0005) and the median (p = .001) va lues of the amplitude distribution function (ADF) and the number of pe riods per minute when the muscle load was below 1% of maximum voluntar y contraction (p = .03). The same clear tendency was also found regard ing the static muscle load from the extensor carpi ulnaris (p = .06). These results indicate the need for reducing the pronation of the fore arm when working with a mouse.