Evaluation of Handle Positions Using Force/Endurance Relationship of an Isometric Holding Task

Almost all the published studies on container handle positions have used the psychophysical, physiological, and biomechanical criteria to evaluate the best handle locations on container. The primary intent of this investigation was to determine if force endurance relationship curves could be used as criterion for comparing the handle positions. Ten subjects participated in a factorial experiment involving four handle positions (2/2, 3/7, 8/8, and 6/8), and four levels of exertion (25%, 50%, 75%, and 100% of maximum lifting capacity). On any treatment condition, the subjects held the box till their endurance limit. The endurance time and the rate of perceived exertion (RPE) were the dependent measures. For the RPE, it was observed that the asymmetric position 6/8 was the best. Similarly the handle position 6/8 had the longest endurance as observed by a third order polynomial fit. The differences among the handle position were consistent across all levels and exertions tested. Further, it appears that the maximum lifting capacity is closer to the grip strength of the non-dominant hand.