Foot Placement Feedback in Physical Training: Effects of Spatial User Interfaces on Performance and Workload in Virtual Reality

Abstract

Agility ladder training is commonly used in fitness and therapy to improve coordination in lower-limb exercises by training precise foot placement. Previous research adapted this training approach to immersive environments and emphasized both the potential and the need for enhanced visual feedback in virtual reality (VR) to improve training outcomes. However, effective visual guidance for such tasks in VR remains underexplored, as it is unclear how spatial user interfaces (UIs) should be designed to support accurate foot placement. To address this gap, we conducted a within-subject study with 40 participants, investigating the effects of two visualization techniques: a Foot-Aligned UI (exocentric, attached to the feet) and a Head-Aligned UI (egocentric, floating in view); combined with color-coded performance feedback. Foot positioning accuracy, rotational control, success rate, and perceived workload were measured during VR-based agility ladder tasks. Results show that the Foot-Aligned UI significantly improved foot placement success rates without increasing cognitive load, compared to the Head-Aligned UI and No UI conditions, which was supported by qualitative feedback. In contrast, color-coded step feedback was perceived as helpful but showed no measurable performance benefit. Based on these findings, we derive design recommendations for spatial UIs to support lower-limb motor training in VR.