Flexion–extension hand torque strengths:: applications in maintenance tasks

Abstract This paper describes the results of an experiment to determine the effects of some task and handle variables on the torquing capabilities of male and female adults in simulated maintenance tasks. Twenty adults generated MVC torques on a 2 1 4  in diameter cylindrical handle with each hand, over 24 different test conditions defined by factorial combinations of four variables – handle surface, wrist action, arm position, and hand laterality. The results showed that extension torques were 1.18 as strong as flexion ones; knurled handle torques, 1.15 as strong as smooth handle ones; right-hand torques, 1.10 as strong as left hand ones; and male torques, 2.04 as strong as female ones. Interaction effects showed that the male–female difference was greater for extension torquing compared to flexion torquing, and from using the knurled handle compared with the smooth one. Also, extension–flexion difference was greater with the knurled than the smooth handle, and with the arm below the horizontal than at other positions. The separate effects of demographic and anthropometric measurements, and handgrip and pinch strengths are also discussed in this paper. Relevance to industry The results of this study enhances our understanding of torquing on large diameter cylindrical handles and provide useful data for designing tasks involving such torquing, especially in the maintenance environment.