Pressure or Movement? Usability of Multi-Functional Foot-Based Interfaces

Despite considerable prior work exploring foot-based interaction techniques, direct comparisons of the performance of these approaches have been lacking. Here, we compare the performance of the two most common approaches found in previous studies: rocking (applying pressure to different parts of the foot) versus rotating and sliding, considering the use case of a hands-free interface intended for seated musicians. Participants performed a number of representative operations, such as setting the tempo of a metronome, using the two strategies. Results indicate superiority of the rotating and sliding approach, both in completion time and responses to NASA TLX questionnaires, although rocking was preferred by some participants due to its ergonomics and subtle movements required for parameter-controlling tasks. Beyond the comparison itself, the decisions we faced related to menu design and feedback for our use case may offer helpful insight for the design of future foot-based interfaces.