Screen-Directed Stretching: Supporting Ergonomic Neck Stretching in XR Workspaces

Paper Title

Screen-Directed Stretching: Supporting Ergonomic Neck Stretching in XR Workspaces

Publication Info

• Topic area: Ergonomic interventions for musculoskeletal health in XR workspaces
• Keywords: Extended reality, neck stretching, ergonomics, virtual screen repositioning, musculoskeletal disorders, XR workspaces, posture guidance, task efficiency, user experience, human-computer interaction

Background and Problem

• Problem / challenge: Many workers fail to adopt habitual static stretching due to a lack of knowledge about proper techniques and the need to interrupt ongoing tasks.
• Significance: Addressing this issue could improve worker productivity, reduce musculoskeletal disorders (MSDs), and enhance well-being.
• Motivation and related work:
  • Prior HCI research has explored physical activity promotion through interactive systems, posture guidance, and dynamic screen positioning. However, these approaches do not adequately integrate stretching into work routines without interruptions.
  • XR environments offer unique opportunities for dynamic content positioning, but their potential for guiding stretching exercises remains unexplored.

Solution

• Proposed approach: Screen-Directed Stretching, a technique that repositions virtual screens in XR workspaces to guide users through neck stretching exercises without interrupting their tasks.
• Novelty:
  1. Introduction of a posture-guiding system that integrates stretching into XR workspaces without task interruption.
  2. Exploration of screen coordinate systems (world-bound vs. body-bound) and transition patterns (Slide vs. Jump) for effective and user-friendly stretching guidance.
  3. Development and evaluation of a VR-based prototype to assess task performance and user experience during stretching.
  4. Insights into balancing workability and stretching efficacy through hybrid coordinate systems.
• Procedure and key techniques:
  • Reposition virtual screens in yaw, pitch, and roll directions to induce neck stretching.
  • Use a hybrid coordinate system that switches between world-bound (WB) for tasks and body-bound (BB) for stretching.
  • Implement screen transitions (Slide for continuous movement, Jump for discrete repositioning).
  • Conduct user studies to evaluate stretching achievement rates, task performance, and user experience.

Results

• Concrete findings:
  • Stretching achievement rate: 90.98% (SD = 7.60%).
  • No significant degradation in task performance (reading mora count, typed letter count, typing error rate) between stretching (SDS) and no-stretching (NS) conditions.
  • Subjective distraction was higher in SDS, but simulator sickness and workload were equivalent across conditions.
• Advantage over baselines:
  • SDS effectively induced neck stretching without significantly impacting task efficiency or causing simulator sickness.
  • BB coordinate system showed higher efficacy in guiding stretching compared to WB in scenarios where users were unaware of the stretching purpose.
• Experiments / evaluation:
  • Two preliminary user studies (PUS1, N = 8; PUS2, N = 6) explored design variables (coordinate systems, transition patterns) and stretching efficacy.
  • A main user study (N = 16) evaluated task performance, subjective workload, and stretching experience during reading and typing tasks in XR.
• Limitations and future work:
  • Limited sample size and participant diversity (young, university students).
  • Short-term evaluation; long-term effects on MSD prevention and well-being remain unexplored.
  • Applicability to more complex tasks and AR/MR environments needs further investigation.
  • Future work includes optimizing HMD design, integrating eye tracking, and exploring adaptive stretching frequencies.

Summary

Screen-Directed Stretching introduces a novel method for integrating ergonomic neck stretching into XR workspaces by dynamically repositioning virtual screens. User studies demonstrated that the technique effectively induces stretching without significant impacts on task performance, though subjective distraction was noted. The findings suggest potential for improving worker health and productivity, particularly for those with prior neck stiffness. Future research will focus on broader participant demographics, long-term effects, and implementation in AR/MR environments.