Influence of Input Hardware and Work Surface Angle on Upper Limb Posture in a Hybrid Computer Workstation

Area of Science:

• Ergonomics and Human Factors
• Occupational Health
• Biomechanics

Background:

• Modern offices increasingly use sit-stand and tablet workstations to enhance worker mobility.
• However, these setups can lead to non-neutral upper-limb postures, potentially causing joint issues.
• Hybrid standing workstations may offer a solution for improving working postures.

Purpose of the Study:

• To evaluate how work surface angle and input hardware affect upper-limb posture.
• To assess the impact of hybrid computer workstations on posture.
• To identify optimal configurations for different office tasks.

Main Methods:

• Fourteen participants used a hybrid workstation in four configurations: horizontal/sloped surface with computer/tablet.
• Three-dimensional upper-limb postures were captured during reading, form filling, and email writing tasks.
• Posture data was analyzed using amplitude probability distribution functions to determine median and range.

Main Results:

• A sloped-surface tablet configuration reduced wrist ulnar deviation by 5° during reading compared to a horizontal-surface computer.
• Neutral joint postures for shoulder, elbow, and wrist were most common with computer input on a horizontal surface.
• Elbows were more extended (23°, 15°) and wrists less ulnar deviated (6°) during reading versus typing.

Conclusions:

• Recommend horizontal-surface computers for typing tasks.
• Recommend sloped-surface tablets for intermittent reading tasks.
• Hybrid workstations can promote posture variation for mobile office workers, but further research is needed.