The goal of this project is to evaluate the extended use of multi-touch interactiontechniques, more specifically the ergonomic convenience of existing bimanual andunimanual interaction techniques and personal preference over an extended period of time for both horizontal and vertical tabletops. Objective localized muscle fatigue, muscle activity, and subjective perceived exertion measures were administrated. In the experimental design, electromyograms were recorded during tabletop interaction technique and voluntary isometric contractions were recorded pre- and post-tabletop activity for the biceps brachii, middle deltoid, and extensor digitorum for both sides of the body. Changes in the median power frequency (MPF) and root mean square (RMS) were explored to examine muscular fatigue and activity respectively. MPF was found sensitive to fatigue for some muscles on both the horizontal and vertical condition where a decline in MPF was noted, albeit statistically insignificant. Perceived exertion ratings have shown an increase by the end of the task where the difference between the means was found to be statistically significant for the vertical condition but not the horizontal one. The electromyograms recordings, along with video recordings, have shown the sustainability of the interaction techniques adopted at the beginning of the task to the end of that task, which included both unimanual and bimanual techniques.
An Evaluation of Extended Duration Multi-touch Interaction