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People developing transient low back pain during standing have altered control of their spine and hips during standing tasks, but the transfer of these responses to other tasks has not been assessed. This study used video fluoroscopy to assess lumbar spine intervertebral kinematics of people who do and do not develop standing-induced low back pain during a seated chair-tilting task. A total of 9 females and 8 males were categorized as pain developers (5 females and 3 males) or nonpain developers (4 females and 5 males) using a 2-hour standing exposure; pain developers reported transient low back pain and nonpain developers did not. Participants were imaged with sagittal plane fluoroscopy at 25 Hz while cyclically tilting their pelvises anteriorly and posteriorly on an unstable chair. Intervertebral angles, relative contributions, and anterior–posterior translations were measured for the L3/L4, L4/L5, and L5/S1 joints and compared between sexes, pain groups, joints, and tilting directions. Female pain developers experienced more extension in their L5/S1 joints in both tilting directions compared with female nonpain developers, a finding not present in males. The specificity in intervertebral kinematics to sex-pain group combinations suggests that these subgroups of pain developers and nonpain developers may implement different control strategies.
Viggiani and Callaghan are with the Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada. Mannen, Ghiselli, Shelburne, and Davidson are with the Department of Materials and Mechanical Engineering, University of Denver, Denver, CO, USA. Mannen is also with the Department of Orthopaedic Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA. Nelson-Wong is with the School of Physical Therapy, Regis University, Denver, CO, USA. Wong is with Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada.