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Biomechanical effects of sitting with adjustable ischial and lumbar support on occupational low back pain: evaluation of sitting load and back muscle activity.

Authors
Makhsous-M; Lin-F; Bankard-J; Hendrix-RW; Hepler-M; Press-J
Source
BMC Musculoskelet Disord 2009 Feb; 10:17
NIOSHTIC No.
20035423
Abstract
BACKGROUND: Compared to standing posture, sitting decreases lumbar lordosis, increases low back muscle activity, disc pressure, and pressure on the ischium, which are associated with occupational LBP. A sitting device that reduces spinal load and low back muscle activities may help increase sitting comfort and reduce LBP risk. The objective of this study is to investigate the biomechanical effect of sitting with a reduced ischial support and an enhanced lumbar support (Off-Loading) on load, interface pressure and muscle activities. METHODS: A laboratory test in low back pain (LBP) and asymptomatic subjects was designed to test the biomechanical effect of using the Off-Loading sitting posture. The load and interface pressure on seat and the backrest, and back muscle activities associated with usual and this Off-Loading posture were recorded and compared between the two postures. RESULTS: Compared with Normal (sitting upright with full support of the seat and flat backrest) posture, sitting in Off-Loading posture significantly shifted the center of the force and the peak pressure on the seat anteriorly towards the thighs. It also significantly decreased the contact area on the seat and increased that on the backrest. It decreased the lumbar muscle activities significantly. These effects are similar in individuals with and without LBP. CONCLUSION: Sitting with reduced ischial support and enhanced lumbar support resulted in reduced sitting load on the lumbar spine and reduced the lumbar muscular activity, which may potentially reduce sitting-related LBP.
Keywords
Back-injuries; Biomechanics; Biomedical-engineering; Ergonomics; Injuries; Muscles; Muscle-tension; Musculoskeletal-system; Musculoskeletal-system-disorders; Occupational-hazards; Occupational-health; Posture; Skeletal-movement; Skeletal-stress; Skeletal-system; Skeletal-system-disorders
Contact
Mohsen Makhsous, Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL
CODEN
BMDMCE
Publication Date
20090205
Document Type
Journal Article
Email Address
m-makhsous2@northwestern.edu
Funding Amount
145000
Funding Type
Grant
Fiscal Year
2009
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R21-OH-007737
ISSN
1471-2474
Priority Area
Disease and Injury: Low Back Disorders
Source Name
BMC Musculoskeletal Disorders
State
IL
Performing Organization
Rehabilitation Institute Research Corporation
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