Effects of hand placement, handles and support on manual holding tasks

This study recruited 16 participants to examine the effects of hand placement, handles and support on the muscular activities of the musculus biceps brachii and erector spinae, box tilt angle and total center of pressure (CoP) length beneath the feet in manual holding tasks. Each participant was asked to hold a box in two hand placement conditions (symmetrical hand placement and asymmetrical hand placement) × two handle conditions (handles and no handles) × two support conditions (hands-and-body and hands). The results showed that symmetrical hand placement reduced the overall muscular activities of the musculus biceps brachii and erector spinae, box tilt angle and CoP length. The same results were also found in the handles condition and in the hands-and-body support condition. This study recommends that box designers should provide symmetrical handles, and people should keep the box against their front body while holding.