title: Gravitational demand on the neck musculature during tablet computer use.
abstract: 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.
authors: a Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, WA , USA.
authors: Anita N
authors: AN
authors: Vasavada
authors: Derek D
authors: DD
authors: Nevins
authors: Steven M
authors: SM
authors: Monda
authors: Ellis
authors: E
authors: Hughes
authors: David C
authors: DC
authors: Lin
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D034201:Computers, Handheld; D005260:Female; D006112:Gravitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009334:Neck Muscles; D011187:Posture; D013314:Stress, Mechanical; D055815:Young Adult
keywords: biomechanics; neck muscles; posture; tablet computer