Properties of person hoist spreader bars and their influence on sitting/lifting position

The purpose of this study is to analyse mechanical lifts with regard to how the spreader bar design, e.g. frontal length, height and sagittal depth, affects sitting positions and safety during lift and transfer. The seven spreader bars available on the Swedish market had two-point to four-point suspensions. Twelve subjects were photographed individually sitting in each of three types of sling: divided, one-piece with divided leg support, and one-piece. All the slings had significant effects on all specific sitting aspects. However, the spreader bar design only affected the sitting position in the hoist. A long (0.62 m) spreader bar gave a relatively upright sitting position. A deep (0.18 m) spreader bar gave a backward inclination. For all specific sitting aspects, there was a significant interaction between slings and spreader bars. This study demonstrates that the design of the spreader bar, as well as that of the sling, is of decisive importance for the sitting position during lifting.