Abstract

Background: Although, non-specific chronic low back pain (NSCLBP) has been associated with motor control impairments, little is known about the possible driving mechanisms of pain development overtime during prolonged sitting period. Therefore, the purpose of this study was to examine the differences in lumbosacral postures and muscle activities in adults with and without NSCLBP, and their role on pain development during a 1-hour of prolonged sitting task.

Methods: Twenty NSCLBP subjects with motor control impairment (MCI) [10 classified as having flexion pattern (FP) disorder, and 10 with active extension pattern (AEP) disorder], and 10 healthy controls participated in the study. Subjects underwent a 1-hour sitting protocol on a standard office chair. Lumbosacral postures including sacral tilt (ST), third lumbar vertebrae (L3) position, and relative lower lumbar angle (RLLA) were recorded using a two-dimensional inclinometer. In addition, four trunk muscle activities including amplitudes and co-contractions were recorded using electromyography over the 1-hour period. Perceived back pain intensity was recorded using a numeric pain rating scale every 10 minutes throughout the sitting period.

Results: All study groups presented with significantly distinctive lumbosacral kinematics at the lowest level of pain (the beginning of the sitting period) (p<0.05), as well as at the highest level of pain (the end of the sitting period) (p0.05). The MCI subgroups showed a significant deterioration in lumbosacral kinematics and pain levels overtime (p<0.01). The directions of deterioration in lumbosacral kinematics over the 1-hour sitting period occurred in the direction of the motor control impairment (kyphosis for FP subgroup or lordosis for the AEP subgroup). Both MCI subgroups reported a similarly significant increase in pain through mid-sitting (p<0.001). However, after mid-sitting, the AEP subgroup displayed a significantly reversed decrease in the lordotic postures (p=0.001) which was accompanied by much less increase in pain level compared to the FP subgroup. No significantly distinctive trunk muscles’ activities were found at the beginning of sitting (p>0.05), nor did the muscle activities change overtime.

Conclusion: The present study’s findings suggest that MCI subgroups presented with distinctive underlying maladaptive postural patterns. However, the significant increase in pain over the 1-hour sitting might not be only attributed to the inherent maladaptive postures, also it may be related to the directional deterioration in lumbosacral postures overtime.

LLU Discipline

Physical Therapy

Department

Physical Therapy

School

School of Allied Health Professions

First Advisor

Everett Lohman III

Second Advisor

Hatem Jaber

Third Advisor

Noha Daher

Fourth Advisor

Robert Dudley

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

2020

Date (Title Page)

12-2019

Language

English

Library of Congress/MESH Subject Headings

Low Back Pain; Sitting Position; Biomechanical Phenomena

Subject - Local

Low back pain; Motor control impairment; Flexion pattern disorder; Active extension pattern disorder; Prolonged sitting; Lumbosacral kinematics; Muscle Activity

Type

Dissertation

Page Count

xiii, 110 p.

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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