Measuring muscle fatigue during computer mouse use

The goal of this study is to determine whether muscle fatigue can be measured in the finger muscles used to grip the sides of a computer mouse. Ten subjects used a mouse with and without drag-lock intensively for six hours each on two separate days. The mouse was instrumented to continuously measure forces applied to the sides and button of the mouse. Before, during and after mouse use, the subject's level of muscle fatigue in the mousing hand was assessed by measuring the muscle twitch forces resulting from 2 Hz electrical stimulation of the ring finger Flexor Digitorum Superficialis muscle. Subjects applied a mean force equivalent of 0.6% MVC to the sides of both mice during the experiment. Significant levels of muscle fatigue (p = 0.034) were measured after 3 hours of mouse operation and persisted up to 40 minutes after mouse use had ceased. This study demonstrates that muscle fatigue can be measured in the finger muscles after applying prolonged, low level, quasi-static forces to the sides of the mouse.