Biomechanical Loading on the Hand, Wrist, and Forearm When Holding a Tablet Computer

Abstract

OCCUPATIONAL APPLICATIONS Based upon the endurance of their hand and forearm, the maximum duration for holding a computer tablet statically with one hand was less than 10 minutes for many users. In everyday situations, users would likely change posture before this time, but for users whose options are more limited, such as during enterprise use, high levels of fatigue could develop. Therefore, for people in situations where holding a tablet for extended periods of time is required, it would be prudent to change grips frequently, support the tablet on a surface, use aids (such as a stand or strap), hold it with both hands, switch to alternative tasks, and/or take breaks.

TECHNICAL ABSTRACT Background: The use of tablet computers at home and in the workplace has rapidly increased in recent years. Tablet users may hold them for extended periods, increasing the risk of developing fatigue and potential musculoskeletal disorders. Purpose: The goals of this study were to estimate the biomechanical loading on the forearm and hand when holding a tablet computer and to assess the effects of orientation, mass, and the execution of touch gestures on this loading. Methods: Multiple parallel approaches were used to assess an unsupported single-handed grip: maximum load, maximum holding time, biomechanical models to estimate strength demands, ratings of perceived exertion, and grip pressure. Ten males and 10 females participated. Results: A majority (75%) of the participants adopted a modified lateral pinch grip. Using the maximum load method, females exerted a significantly higher percentage of their maximum voluntary contraction than males in landscape orientation (18.5% versus 13.5% maximum voluntary contraction) but not in portrait orientation. In portrait orientation, maximum holding time was 11.5 minutes for females and 15.9 minutes for males. Orientation, but not gesturing, had statistically significant main effects on loading. Conclusions: Holding a tablet one-handed for an extended period of time, as might be found in some enterprise settings, was found to be very fatiguing for the hand; it would thus be prudent for such users to use both hands, support aids, frequent posture changes, or breaks involving rest or alternative tasks.

KEYWORDS:

• Tablet computer
• hand grip
• grip
• fatigue
• holding time
• lateral pinch

FUNDING

This project was partially funded by a research grant provided by the Workplace Safety and Insurance Board (Ontario).