Physical loads on upper extremity muscles while interacting with virtual objects in an augmented reality context

Area of Science:

• Human-Computer Interaction
• Augmented Reality Systems
• Ergonomics and Human Factors

Background:

• Augmented reality (AR) interfaces are increasingly prevalent, offering immersive user experiences.
• A significant challenge in AR is the physical strain experienced by users during interaction.
• Understanding factors contributing to physical load is crucial for designing comfortable AR applications.

Purpose of the Study:

• To examine the impact of movement distance (MD) and target-to-user distance (TTU) on physical load in AR drag-and-drop (DND) tasks.
• To quantify physical load using objective (electromyography) and subjective (NASA-TLX) measures.
• To identify optimal parameters for AR interaction design to minimize user strain.

Main Methods:

• A within-subject experimental design with 5 levels each of MD (16-80 cm) and TTU (40-200 cm).
• Physical load assessed via normalized electromyography (NEMG) of upper extremity muscles and NASA-Task Load Index (TLX).
• Data analysis focused on the main effects and interaction effects of MD and TTU on physical load indicators.

Main Results:

• Both NEMG and subjective workload increased significantly with greater MD.
• NEMG increased as TTU decreased, indicating higher muscle strain with closer targets.
• Subjective workload increased with greater TTU, suggesting perceived effort rises with distance.
• Significant interaction effects between MD and TTU were observed for NEMG.

Conclusions:

• Movement distance and target-to-user distance significantly influence physical load in AR DND tasks.
• Designers should carefully consider MD and TTU to mitigate user physical strain in AR environments.
• Optimizing these parameters can lead to more ergonomic and user-friendly AR interfaces.