This study used two dimensional biomechanical analysis to examine
the effects of back belts and lifting load on selected lifting kinematics
during a simulated patient transfer. A human manikin placed in a sitting
position was attached to a customized lifting apparatus which controlled the
lifting load and direction of the manikin. Eighteen female participants,
between the age of 21 and 27, completed six lifts (sit to stand transfers) of
the manikin. Three lifts were completed at the 30 lb load condition (no belt,
belt 1 and belt 2) and three lifts were completed at the 50 lb load condition
(no belt, belt 1 and belt 2). A doubly two way ANOVA found a significant main
effect for the belt condition,
$F(12,6)=10.06, P=0.002$
. There
was no significant effect for load and no interaction existed between belt and
load. The results revealed a significant decrease in trunk flexion when
participants wore the wider (nine inch) belt during the 30~lb lifts when
compared to the no belt trials. No significant differences were found in trunk
flexion means with the narrower width (six inch) belt. No significant
differences were found in trunk spinal flexion with either belt condition
during the 50 lb lifts. There were no significant differences found in either
of the belts in the means of lifting time, knee flexion, elbow flexion, forward
displacement of the lifter's center of mass, and the lifter's maximum center of
mass velocity. The results suggest that wider back belts may be more effective
at reducing spinal flexion during patient lifting under moderate load
conditions when compared to narrower back belts and to no-belted controls.
