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Horton, Stuart J. MPhty, DipMDT; Johnson, Gillian M. PhD; Skinner, Margot A. PhD
Abstract
Study Design. A repeated measures observational study.
Objective. To investigate change in sagittal alignment of head and neck posture in response to adjustments of an office chair with and without a lumbar roll in situ.
Summary of Background Data. Forward head posture has been identified as a risk factor for neck pain, and there is evidence to show that ergonomic correction in sitting may reduce the incidence of pain. The effect placement of a lumbar roll has on cervical spine posture has not been previously investigated experimentally but rather, is assumed to have a positive influence on head and neck posture.
Methods. Thirty healthy male participants (18–30 years) were photographed while registered in the natural head resting position in each of 4 sitting positions with and without a lumbar roll in situ. Two positions incorporated adjustments to the back rest and 1 to the seat pan of the office chair. The craniovertebral (CV) angle, as a determinant of head and neck posture was measured from the set of digitized photographs obtained for each participant. Comparisons between the CV angle in all postural registrations were made using a mixed model analysis adjusted for multiple comparisons.
Results. Of the positions examined, significant differences in the mean CV angles were found with the backrest of the chair at 100° and at 110° (P < 0.001). With the lumbar roll in situ and the backrest position at 110°, there was a significant increase in the mean CV compared with the angle without the lumbar roll in situ (2.32°, 95% confidence interval: 1.31–3.33; P < 0.001).
Conclusion. The degree of angulation of the backrest support of an office chair plus the addition of lumbar roll support are the 2 most important factors to be taken into account when considering seating factors likely to favorably change head and neck postural alignment, at least in asymptomatic subjects.
Stuart M. McGill, PhD
Professor of Spine Biomechanics,
Department of Kinesiology, Faculty of Applied Health Sciences,
University of Waterloo,
Waterloo, Ontario, Canada, N2L 3G1
Phone: 519-888-4567 ext 36761