The effects of back belts and load on selected lifting kinematics during a simulated patient transfer

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.