Affiliations: Ergonomics Research Laboratory, Department of Physical
Therapy, University of Alberta, Canada
Note: [] Address for correspondence: E.R. Vieira, 3-48 Corbett Hall,
Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada,
T6G 2G4. Tel.: +1 780 492 7187; Fax: +1 780 492 1626; E-mail:
[email protected]
Abstract: Force exertion is related to low back injuries (LBI). This paper
critically reviews the literature concerning cut-points for back force
exertion, presents available guidelines in a concise manner, and identifies
areas that need further research. The studies reviewed were grouped according
to the criteria used to set the cut-point values. Most often cut-points differ
than concur. The approach considering physiological, psychophysical,
epidemiological, and biomechanical aspects of back force exertion meets the
most known criteria and presents the lowest common denominator of instantaneous
load for lifting tasks. Further experimental and epidemiological studies in
peak load and cumulative exposure are necessary. Compound indices should also
be developed for pushing, pulling, and carrying. Future indices should consider
electromyographically determined fatigue, differential viscoelastic properties
of tissues, aging, and the cross sectional area of back muscles. We hope that
this paper contributes to a more systematic appraisal of back force exertion at
work.
Keywords: Spine, work-related low back injuries, low back pain, prevention, physical ergonomics, loads, compression, contraction, psychophysical, strength
