1.4 Ensure that operation requires minimal strength, grip and wrist twisting
Using telecommunications hardware may require a number of physical operations - lifting handsets, pressing buttons or keys, turning knobs or other moving parts, inputting cards or other items and retrieving cards, tickets or other outputs. All these operations should be possible with minimal grip, pushing and pulling strength or twisting of the wrist.
Many, particularly older, users have greatly reduced strength due to degenerative conditions that affect muscle power or restrict movements of the joints in the fingers, hands and wrists. Most telephones need to be gripped and most operations require finger or hand movements. If the handset is awkward, the controls too stiff, the phone card slot too narrow or the machine's grip on the card too tight, some users may not have the strength to overcome this and will be unable to use the device.
Directions and Techniques
Favour pressing, but with modest force
As far as possible, avoid using controls that have to be gripped and turned rather than pressed. Allow for a maximum pressing force of 5lbf.
Do not grip outputs too tightly
Ensure that the machine's grip on outputs such as returned phone cards is no more than is necessary to prevent them falling out or being pulled out by the wind.
Ensure handsets are light, well-balanced and ergonomically designed
Handsets should be easy to lift and hold for users with limited grip strength. It helps to have a gap between the handset and the base unit if there is one, so that the user can curl their fingers around the handset before picking it up. Handsets should also be designed to be easy to hold to the ear and mouth for people with limited wrist movement.
Avoid moving parts or design them carefully
Moving parts, such as antennas and flaps on mobile phones, should either be avoided or designed to be easy to use with one-hand, weak grip strength and limited dexterity.
How you could check for this:
Test with real users
To test for this, you should have a prototype used in a realistic situation by real people, particularly older people.
About user testing