AnkleType: A Hands- and Eyes-free Foot-based Text Entry Technique in Virtual Reality

2026-03-23

AI Summary

This work proposes AnkleType, a hands-free and eyes-free text input technique for virtual reality that leverages ankle gestures—introducing foot-based interaction to VR text entry for the first time. Designed to preserve immersion by eliminating reliance on hand manipulation or visual fixation, AnkleType supports both seated and standing postures through bimanual (BPSit) and unimanual (UPStand) input strategies. Through iterative gesture elicitation, spatial perception studies, language modeling, and a longitudinal user study, the system’s keyboard layout and interaction protocols were optimized. Results demonstrate that users achieved initial typing speeds of 8.99–9.13 words per minute (WPM), improving to 15.05–16.70 WPM under visual conditions and 11.15–12.87 WPM in eyes-free scenarios after seven days of training, thereby enabling efficient, usable, and immersive text input in VR.

Technology Category

• Humans and AI: Game Design — Virtual Humans, NPCs and Autonomous Characters
• Computer Vision: Biometrics, Face, Gesture & Pose
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Security and Privacy: Large-scale security measurements

Abstract

Virtual Reality (VR) emphasizes immersive experiences, while text entry often requires hands or visual attention, which may disrupt the interaction flows in VR. We present AnkleType, a hand- and eye-free text-entry technique that leverages ankle-based gestures for both standing and sitting situations. We began with two preliminary studies: one investigated the movement range of users' ankles, and the other elicited user-preferred ankle gestures for text-entry-related operations. The findings of these two studies guided our design of AnkleType. To optimize AnkleType's keyboard layout for eye-free input, we conducted a user study to capture the users' natural ankle spatial awareness with a computer-simulated language test. Through a pairwise comparison study, we designed a bipedal input strategy for sitting (BPSit) and a unipedal input strategy for standing (UPStand). Our first in-VR text-entry evaluation with 16 participants demonstrated that our methods could support the average typing speed from 8.99 WPM (BPSit) to 9.13 WPM (UPStand) for our first-time users. We further evaluated our design with a 7-day longitudinal study with twelve participants. Participants achieved an average typing speed of 15.05 WPM with UPStand and 16.70 WPM with BPSit in the visual condition, and 11.15 WPM and 12.87 WPM, respectively in the eyes-free condition.

Problem

• Virtual Reality
• Text Entry
• Hands-free Interaction
• Eyes-free Interaction
• Ankle-based Input

Innovation

• foot-based interaction
• hands-free text entry
• eyes-free input
• ankle gestures
• virtual reality