Gravitational demand on the neck musculature during tablet computer use

• Published in: Ergonomics Vol. 58; no. 6; pp. 990 - 1004
• Main Authors: Vasavada, Anita N., Nevins, Derek D., Monda, Steven M., Hughes, Ellis, Lin, David C.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 03.06.2015; Taylor & Francis LLC
• Subjects: Adult; Biomechanical Phenomena; Biomechanics; Computers, Handheld; Demand; Ergonomics; Female; Gravitation; Gravity; Guidelines; Humans; Male; Mathematical models; Middle Aged; Muscles; Muscular system; Neck; Neck Muscles; Necks; Pain; Portable computers; Posture; Risk factors; Stress, Mechanical; tablet computer; Tablet computers; Young Adult; biomechanics; tablet computer; neck muscles; posture
• ISSN: 0014-0139; 1366-5847; 1366-5847
• DOI: 10.1080/00140139.2015.1005166

Tablet computer use requires substantial head and neck flexion, which is a risk factor for neck pain. The goal of this study was to evaluate the biomechanics of the head-neck system during seated tablet computer use under a variety of conditions. A physiologically relevant variable, gravitational demand (the ratio of gravitational moment due to the weight of the head to maximal muscle moment capacity), was estimated using a musculoskeletal model incorporating subject-specific size and intervertebral postures from radiographs. Gravitational demand in postures adopted during tablet computer use was 3-5 times that of the neutral posture, with the lowest demand when the tablet was in a high propped position. Moreover, the estimated gravitational demand could be correlated to head and neck postural measures (0.48 < R 2  < 0.64, p < 0.001). These findings provide quantitative data about mechanical requirements on the neck musculature during tablet computer use and are important for developing ergonomics guidelines. Practitioner Summary: Flexed head and neck postures occur during tablet computer use and are implicated in neck pain. The mechanical demand on the neck muscles was estimated to increase 3-5 times during seated tablet computer use versus seated neutral posture, with the lowest demand in a high propped tablet position but few differences in other conditions.