EFFECT OF TOOL SHAPE AND WORK LOCATION ON PERCEIVED EXERTION FOR WORKON HORIZONTAL SURFACES

Thirty subjects drove screws into perforated sheet metal mounted on a horizontal surface using three air-powered tools that varied in shape (right-angle, in-line, and pistol-shaped). The four horizontal work lo cations ranged from 13-88 cm in front of the body and were placed at 2 5 cm intervals. The vertical placement of the horizontal beam was at m idthigh, elbow, and midchest height. Subjects drove 25 screws at each tool/work location combination before rating that condition using the Borg 10-point ratio rating scale. The ratings of perceived exertion in creased with increasing horizontal distance from the body. When tool s hape was not considered, the perceived exertion was virtually equal fo r driving screws at midthigh or elbow height. The ratings at midchest height were significantly higher than elbow and midthigh height. When tool shape was taken into account, subjects perceived less exertion dr iving screws with the pistol-shaped tool at midthigh height. The in-li ne and right-angle tools had the lowest ratings of perceived exertion for driving screws at elbow and midchest height.