A novel device for evaluating forces during the dynamic jar opening action--do older and younger adults do things differently?

Package opening tasks have been identified as some of the most challenging that individuals need to perform to access food. There is little previous study of the 3D hand loading that is required to open these products. A novel load measuring device was used to characterise torque, squeeze and compression forces during the dynamic action of jar opening for young and older adults. The current study showed that the older adults used lower squeeze forces (86.1 N vs. 95.4 N) and higher compressive forces (26.9 N vs. 25.2 N) on the jar lid than younger adults. Older adults tended to apply loading to the jar lid slower (0.038 Nm/s vs. 0.044 Nm/s) and to open the jar at a slower rate (0.84 Rad/s vs. 1.59 Rad/s) than young adults whilst using a higher proportion of their maximal grip strength (40% vs. 27%) indicating that older adults used a more cautious opening strategy. These differences suggest that a simple maximal torque test is not sufficient to characterise older adults' abilities in relation to package opening. The loading required to open packaging should be understood to ensure that packaging design is developed to be inclusive. This is the first report of realistic complex packaging opening loading presented in the literature.