The Impact of Dual Computer Screen Size on Neck Discomfort

Background: Work related musculoskeletal disorders are problems experienced in a variety of vocations. Office-based tasks' inherent static and repetitive nature introduces a unique set of ergonomic challenges. One of the most conspicuous changes in office work settings is the increasing size of computer monitors and displays. This project focused on whether or not these ever-enlarging computer screens may contribute to neck discomfort by directly measuring neck and shoulder muscle activity of participants when they are interacting with different size computer displays. Purpose: The research helped determine if there exists a statistically relevant correlation between size of display and muscle activity of the neck and shoulder. This knowledge could be used to provide information on what size monitors would best mitigate neck discomfort. Methods: Thirty volunteers performed two types of computer-interfacing tasks using dual 20” computer monitors and repeating the 2.5 minute tasks with dual 32” computer monitors: (1) typing a written script, and (2) playing a drag-anddrop game. Direct bilateral measurements of activities of the sternocleidomastoid and upper trapezius were taken using surface electromyography. Additionally, each participant completed demographic and discomfort surveys following each task. Results: Muscle engagement of the left sternocleidomastoid showed statistically significant increase during the typing and drag-and-drop exercises while using the larger monitor displays. Whereas, the size of the monitors did not influence the muscle engagement of the upper trapezius during the drag-and-drop exercise, but there was a statistical significant increase for that muscle during the typing exercise. Conclusions: Larger dual monitor displays could contribute to an increase in neck discomfort for workers engaged in typing and mousing work activities.