title: Timing and magnitude of lumbar spine contribution to trunk forward bending and backward return in patients with acute low back pain.
abstract: Alterations in the lumbo-pelvic coordination denote changes in neuromuscular control of trunk motion as well as load sharing between passive and active tissues in the lower back. Differences in timing and magnitude aspects of lumbo-pelvic coordination between patients with chronic low back pain (LBP) and asymptomatic individuals have been reported; yet, the literature on lumbo-pelvic coordination in patients with acute LBP is scant. A case-control study was conducted to explore the differences in timing and magnitude aspects of lumbo-pelvic coordination between females with (n=19) and without (n=19) acute LBP. Participants in each group completed one experimental session wherein they performed trunk forward bending and backward return at preferred and fast paces. The amount of lumbar contribution to trunk motion (as the magnitude aspect) as well as the mean absolute relative phase (MARP) and deviation phase (DP) between thoracic and pelvic rotations (as the timing aspect) of lumbo-pelvic coordination were calculated. The lumbar contribution to trunk motion in the 2nd and the 3rd quarters of both forward bending and backward return phases was significantly smaller in the patient than the control group. The MARP and the DP were smaller in the patient vs. the control group during entire motion. The reduced lumbar contribution to trunk motion as well as the more in-phase and less variable lumbo-pelvic coordination in patients with acute LBP compared to the asymptomatic controls is likely the result of a neuromuscular adaptation to reduce painful deformation and to protect injured lower back tissues.
authors.affiliation: F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Iman
authors.initials: I
authors.lastname: Shojaei
authors.affiliation: F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Milad
authors.initials: M
authors.lastname: Vazirian
authors.affiliation: College of Nursing, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Salt
authors.affiliation: Program in Physical Therapy, Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, MO 63108, USA.
authors.forename: Linda R
authors.initials: LR
authors.lastname: Van Dillen
authors.affiliation: F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA. Electronic address: babak.bazrgari@uky.edu.
authors.forename: Babak
authors.initials: B
authors.lastname: Bazrgari
mesh_terms: D000208:Acute Disease; D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000502:physiology*; D008875:Middle Aged; D016059:Range of Motion, Articular; D060726:Torso / Q000502:physiology*
keywords: Acute low back pain; Continuous relative phase; Lumbo-pelvic coordination; Timing and magnitude aspects; Trunk forward bending and backward return