Abstract
The objective of this study was to determine whether there are differences in hand muscle activities (APB : abductor pollicis brevis, ED : extensor digitorum, ECU : extensor carpi ulnaris, and EI : extensor indicis) and subjective discomfort according to the three mouse sizes (small, medium, large) and two task types (pointing and scrolling). The mouse size and task type showed significant interaction effects on the total NEMG (p = 0.004) and on the NEMG of the abductor pollicis brevis muscle (p = 0.001). The total NEMG and the NEMG of APB showed the highest value in the 'scrolling' task using the 'small' mouse. However, the NEMG of the EI was different according to the mouse size, and the 'small' mouse showed the lowest value. The subjective discomfort was the lowest in the 'medium' mouse, and all nine subjects preferred the 'medium' size. The hand-size related anthropometric variables showed different correlations according to the task type and mouse size with the NEMGs and subjective discomfort. The results of this study could be used as a basic information for the determination of the proper mouse size according to the hand size.