Much attention has been given to the ergonomic design of the mouse, yet virtually no research has been conducted on where the mouse should be located. Recent concerns that sustained mouse use can increase risks of CTDs is prompting reexamination of the optimal location for mouse use.
This page describes surface EMG results from a preliminary study of the effects of the horizontal location of the mouse on shoulder muscle (right deltoid) activity. All tests were done with a Microsoft mouse on an adjustable position mouse platform that was 27.5 inches above the floor.
For each trial the right shoulder abduction angle was set, using a goniometer, and the mouse platform position adjusted so that the mouse was positioned in the center of the platform and straight ahead of the forward pointing forearm. For each trial the subject moved the mouse from the central position to the top right corner of the mousepad, and then around the perimeter of the pad in a clockwise direction to each of the four corners of the mousepad four times in succession. Surface EMG measures (raw signal and rms) were taken using the Flexcomp system. Recordings were taken for the right arm at 10, 20, 30, 40, 50, and 60 degrees abduction, and also for mouse use on the desk top.
Results were dramatic, showing almost a 1:1 linear increase in EMG activity with increased shoulder abduction. These results are summarized in a downloadable .pdf file (readable using Adobe Acrobat - http://www.adobe.com).
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