Affiliations: Department of Kinesiology, Faculty of Applied Health
Sciences, University of Waterloo, Waterloo, Ontario, Canada
Note: [] Address for correspondence: Dr. Jack P. Callaghan, Department
of Kinesiology, University of Waterloo, 200 University Ave. W, Waterloo, ON,
N2L 3G1, Canada. Tel.: +1 519 888 4567 x37080; Fax: +1 519 746 6776; E-mail:
callagha@healthy.uwaterloo.ca
Abstract: Background: Little is known about how lumbar spine movement
influences mechanical changes and the potential injurious effects of prolonged
flexion associated with seated postures. The purpose of this study was to
examine the postural responses and pain scores of low back pain sufferers
compared with asymptomatic individuals during prolonged sitting in order to
understand the biomechanical factors that may be associated with sitting
induced low back pain. Method: Sixteen participants with
sitting-aggravated low back pain were age- and gender-matched with 16
asymptomatic participants. Tri-axial accelerometers were used to monitor lumbar
spine angles during 90 minutes of seated computer work. Lumbar spine postures
were examined using a movement pattern analysis of two types of postural
adjustments, termed shifts (step-like adjustments larger than 5° and
fidgets (small change and return to approximately the same position). Results: The LBP group reported large significant increases (P < 0.0001)
in low back pain while asymptomatic individuals reported little to no pain. On
average, every participant fidgeted every 40 to 50 seconds. However, only the
LBP sufferers demonstrated a significant increase (P=0.04) in the number of
shifts over 90 minutes of seated work; the LBP group shifted every 4 minutes in
the last 30 minutes of sitting compared to every 10 minutes for the
asymptomatic group. LBP sufferers also demonstrated larger amplitudes of shifts
and fidgets when compared to the asymptomatic group. Conclusion: Greater and more frequent movement was not beneficial and did not reduce pain in
individuals with pre-existing LBP. Future work to understand the biomechanical
effects of proactively inducing movement may help to explain the paradox of the
relationship between movement and pain.
Keywords: Lumbar spine, pain, seated work, movement
