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Marras W. S. and Granata K. P.
Biodynamics Laboratory, The Ohio State University
This experiment measured body kinematics, trunk muscle activity
and predicted spine loading as 15 male subjects lifted loads
both symmetrically and asymmetrically. The four belt conditions
consisted of no belt, a leather weight lifting belt, an elastic
lifting belt and a belt with a built-in orthotic that maintained
a lordotic curve in the trunk.
Collectively, the results showed the elastic lifting belt
was the only belt that significantly reduced the trunk range
of motion as well as influencing muscle activity and spinal load
compared to the unbelted condition. Load reduction while using
the elastic belt was more prominent for asymmetric lifting. Elastic
belts reduced the peak compression by nearly 7% during sagittal
lifting, whereas, a 12% reduction was seen during asymmetric
lifting.
One might speculate at this point why the elastic belt affected
trunk motion and spine load to a much greater degree than the
other belts did. The elastic belt was unique in that it was much
wider than the other belts. It had the effect of joining the
pelvis and the thoracic region of the spine, whereas, the other
belts simply resided between the thorax and the iliac crest.
It was interesting to note that the only other belt that resulted
in any significant reaction at all was the orthotic belt which
also partially joined these parts of the trunk.
"In the four belt and non-belt conditions studied,
only the elastic lifting belt reduced the trunk range of motion
and influenced muscle activity and spinal load."
William S. Marras, PhD
Presented at the 42nd Annual Meeting, Orthopædic
Research Society, February 1996, Atlanta, GA.
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