Measuring the Effects of Head-Worn Device Mass on Head Kinematics

Head-worn devices (HWDs) add mass and alter mass distribution on the head–neck system, yet their effects on head kinematics and user response remain poorly quantified. This study developed a participant-specific method to evaluate HWD mass effects during yaw-dominant visual-search and head-tracking tasks. Three-dimensional head kinematics were measured with optical motion capture, while skull motion was tracked independently from the headset using a mouthguard-based rigid body. Participant-specific 3D head scans, anatomical landmarks, and digitized headset center-of-mass locations were used to spatially register device loading relative to individual head geometry. Outcomes included angular displacement, peak angular acceleration, and ratings of effort, discomfort, weight, and stability. Preliminary results indicated that greater HWD mass was associated with lower peak yaw angular acceleration, while perceived-weight ratings increased with mass. Anthropometric measures were included to examine individual variability. The framework links HWD physical properties, head–neck kinematics, and user experience to support validation and inclusive design guidance.