This Chase Ergonomics, Inc. review
of the NIOSH study was read and approved by Mr. Hongwei Hsiao,
PhD, Chief, Protective Technology Branch, NIOSH-DSR .
Reproduction prohibited without express
written permission from Chase Ergonomics, Inc.
To order reprints of the study or to
read it online, click here:
SPINE JNL
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A review of the first NIOSH biomechanical study of back support
use
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The Effect of Wearing a Back Belt on
Spine Kinematics During Asymmetric Lifting of Large and Small
Boxes
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Preface: This research, designed to simulate an actual
work situation, was published in August 2001 in Spine, An
International Journal for the Study of the Spine, Volume
26, Number 16, pp 1794-98. The study was conducted at the Division
of Safety Research, National Institute for Occupational Safety
and Health (NIOSH), Morgantown, West Virginia.
Back supports used in this laboratory study were identical to
those tested in a companion NIOSH epidemiology study, "A
Prospective Study of Back Belts for Prevention of Back Pain and
Injury", published in the Journal of the American Medical
Association, December 6, 2000, Vol 284. No. 21.
Background: Prior to these companion studies, NIOSH
had published only an external review of back support literature
"Workplace Use of Back Belts: Review and Recommendations,"(NIOSH
Back Belt Working Group, DHHS (NIOSH) Number 94-122, 1994) and
a brief consumer-oriented brochure "Back Belts: Do They
Prevent Injury?" (NIOSH Publication No. 94-127, 1994), which
does not include scientific citations in the text.
"Workplace Use of Back Belts: Review and Recommendations"
reviewed sixteen physical studies and four epidemiological studies,
each evaluating the use of some form of back support (belt).
A wide variety of back support apparatus was used for these
studies, including:
leather weightlifting belt, fabric weightlifting belt, soft
neoprene belt without stays, elastic back support with molded
plastic inserts, medical support, narrow semi-elastic corset,
narrow fabric corset, long fabric corset, leather-covered steel
brace, polyethylene jacket, common prescription brace, lumbosacral
corset, chair-back brace, thoracolumbosacral (full back) brace,
prescription orthoses of various designs and an inflatable elastic
belt.
The NIOSH working group's conclusion in 1994 was "the
effectiveness of using back belts to lessen the risk of back
injury among uninjured workers remains unproven."
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The Effect of Wearing a Back Belt on
Spine Kinematics During Asymmetric Lifting of Large and Small
Boxes
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Rebecca Giorcelli, PHD*, Richard E. Hughes, PhD**, James
T. Wassell, PhD*, Hongwei Hsiao, PhD*
*National Institute for Occupational Safety and Health
(NIOSH), Division of Safety Research, Morgantown, West Virginia.
**University of Michigan, Ann Arbor, Michigan, Orthopaedic
Research Laboratories, Section of Orthopaedic Surgery.
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Introduction: "The Effect of Wearing a Back
Belt on Spine Kinematics During Asymmetric Lifting of Large and
Small Boxes" was a laboratory study designed to simulate
an actual work situation. An elastic back support used in industrial
settings was worn according to manufacturer's instructions while
boxes were lifted.
The primary objective of the study was to investigate the
effects of elastic lumbar back supports on spine kinematics during
asymmetrical lifting of small and large boxes.
The secondary objective was to test for a possible carryover
or learning effect of back support use on kinematics between
trials, which might influence the results of back support studies.
Method: Seventeen male and eleven female subjects with
at least 6 months of material handling experience lifted large
and small boxes from a pallet to a height of 79 cm, turning 60
degrees to the right at the top of the lift. Participants had
no history of lower back pain and averaged 29.5 years of age.
Seventeen minute lifting periods were followed by equal resting
periods. Subjects lifted 50 times in each of three separate sessions,
resulting in 150 lifts per subject.
Results: Wearing an elastic back support while lifting
either the large or the small box significantly reduced maximum
spine flexion, maximum flexion angular velocity and maximum extension
angular velocity.
Knee and hip maximum flexion increased significantly while wearing
a belt. Lateral bending and twisting while wearing the belt were
reduced when lifting the large box. No significant carryover
effects between trials were detected from wearing back supports.
Discussion: The use of elastic back supports (belts)
significantly affected spine kinematics. While lifting small
and large boxes on a sagittal plane, motions were reduced. Torso
movement was reduced while wearing a back support and lifting
the large box. Flexion of knees and hip increased while wearing
back supports and performing lifts of both small and large boxes.
"The subjects lifted more slowly when
wearing the belt. . . .Considering that belt use also decreased
torso movements, it appears that using a back support belt causes
the subject to use more of a squat-lift technique as opposed
to a stooping technique." (pg. 1797)
The researchers whose work is reviewed here are not endorsing
any specific product or manufacturer. These studies were originally
published in peer-reviewed journals and appear here in a condensed
form. ©2001, Chase Ergonomics, Inc.
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