Alternating hands when interacting with a desktop touchscreen can reduce physical efforts of the shoulder muscles

Abstract

Finger-touch interface has not been widely adopted to desktop touchscreen displays as it requires entire arm movements and causes resultant arm and shoulder discomforts. As one of possible ways to lessen the physical discomfort of the touchscreen users, this study investigated potential benefits of an ‘alternating hands’ strategy in interacting with a desktop touchscreen display. Twenty three participants conducted cyclic reach-tap-return operations on a 23” desktop touchscreen in three different touch strategies (‘left- hand only’, ‘right-hand only’ and ‘alternating hands’) and with the display in three positions (near flat, upright-distant and upright-close). Mean and integrated myoelectric activity (EMG) of the left and right shoulder muscles were compared between the nine conditions. Two-way ANOVA found that the‘alternating hands’ (participants freely switched hands depending on target location) strategy resulted in significantly less amount of total mean and integrated EMG of the shoulder muscles compared to the other two strategies (p<0.01). Among the three display positions, participants used shoulder muscles significantly less when the display was in the ‘near flat’ position than when the display was in the other two positions. Study results suggest that the ‘alternating hands’ strategy should be recommended for desktop touchscreen users to reduce physical efforts of shoulder muscles.