Muscular Activity in Relation to Support of the Upper Extremity in Work With a Computer Mouse

The objective of this study was to compare the effects of using a forearm or wrist support on muscular load in the forearm and neck-shoulder region during work with a computer mouse. Fourteen 35- to 50-year-old healthy women who worked with a video display unit for at least 4 hr a day in an office and who also used a computer mouse for at least 2 hr a day participated in this experimental study. In the laboratory, computer mouse use with the forearm supported was compared with computer mouse use with the wrist supported. The participants edited a text table by moving symbols from one square to another in a fixed order. Each trial was a set of 64 movements. The trials were repeated 10 times in random order, 5 trials with each method of support. The dependent variable was electromyographic activity measured from muscles in the preferred lower arm and in the neck-shoulder region. Normalization to the individual mean of each participant was found to be more effective in reducing the interindividual variation ...