“Fancy a Brew? “: Understanding factors influencing ease of use of cups used in care homes

Background and Aims

There are a wide variety of different designs for mugs and cups, but these are primarily driven by visual aesthetics rather than utility. The range of drinking vessels available to the care home sector is limited and not informed by ergonomic considerations that would make them more suitable for the frail elderly to use. Although our previous work has thrown some light on this problem, there is a need to improve our understanding of the ergonomics of drinking and drinking vessels to better inform both the designs available and purchasing decisions of facilities caring for older people.

Methods

This study was split into two phases, an initial qualitative focus group study and a quantitative ergonomic analysis.

Results

From the focus group study, two cups were preferred of the five presented. The characteristics shared by these two cups were lightness and large handle. From the ergonomic analysis the general grip observed in this to hold a cup can be classified as a power grip with an adducted thumb. Cups with a relatively low mass (m), a handle orifice area (S) sufficient to allow a minimum of two fingers to pass through comfortably whilst offering the ability to be supported by an adducted thumb and ring finger comfortably are seen to perform best. Further, whilst the handle orifice area should be sufficiently large for the optimal grip to be used it should also minimize the moment on the user's wrist. Computed finger forces show considerable variability across the fingers and across the cups. All the forces calculated from the simulation are relatively low for power grips of the type described earlier. This indicates that the individual finger grip forces are less of an issue for users than the stability needed to control and balance the force in the wrist.

Conclusion

This study has also shown that there are several critical dimensions for the design of cups for people with reduced strength and dexterity. The mass of the cup (m), the diameter of the cup D, the handle length L, and the orifice area S effecting the critical moment on the wrist and the ability to support this moment through the fingers.