Dexterity, Strength, Balance, and Stamina

Have you ever tried to lift a 20-pound (9 kg) box of laundry detergent and place it on a shelf above your head using only one arm? Or struggled to lift a wiggling and wet 25-pound (11 kg) child out of a bathtub?

Included in this user group are those who are fatigued or frail from illness or age, and the multi­tudes of people with limited upper body strength. Also included are individuals with pain, or lim­ited joint or muscle motion, including the ability to grip or grasp, due to temporary or minor injuries and illness. Specific conditions include arthritis, carpel tunnel syndrome, asthma, allergies, chemical sensitivities, post-polio syndrome, stroke, Parkinson’s disease, multiple sclerosis, ALS, cerebral palsy, and numerous additional unique physical conditions.

As we age, we experience a decrease in strength due to bone density and muscle loss, causing an increase in accidents and fractures. Decreased mobility can be caused by changes in joints, stooped posture, and/or decrease in height, and common disorders such as arthritis, osteoarthritis, and osteoporosis. As we "shrink" in height, our reach ranges become shorter than those of middle – aged people, moving closer to the range of children.

Changes in internal functions can cause increased incidence of high blood sugar, gallstones, diver­ticulitis, constipation, and loss of bowel control. Changes in kidney and bladder function can in­hibit urinary control and cause dehydration. Changes in the nervous system result in slower movements, and decreased balance and coordination due to inefficiency of the nervous system and central brain processes. Many people experience a sleeping pattern change, requiring less sleep or experiencing less sound sleep.

A concern with this client is the prognosis, and how the condition will likely change, another critical issue that can be clarified by involved medical professionals. Strength and pace may vary throughout the day. If a cane, walker, or other mobility aid is needed, the ability to carry things is often compromised. Observe your client’s balance, and how he/she lifts and moves his/her feet.

Pay special attention to design concepts such as clear floor space, options to sit or stand, reach ranges, design of supports, drawer pulls and controls for ease of use, particularly the strength/ dexterity needed for operation and safety. These and other design considerations are detailed in the section that follows.

Stature

Do you remember, as a child, trying to reach the faucet at the lavatory? Children and others small in stature have reduced reach. A child’s stature at age six is closer to that of a seated adult than it is to even the shortest of standing adult females (see Figure 8.1).

In contrast, those taller than average height can experience fatigue from operating in a stooped position at fixtures and fittings planned for the comfortable use of an average height person.

Pay special attention to design concepts such as reach ranges, whether unobstructed or over a counter or fixture, selection of supports including step stools, drawer pulls and controls for ease of use and safety, and sight lines. These and other design considerations are detailed in the section that follows.

Some key examples of the universal design principles in chapter 4, "Universal Design and Human Factors," that become more critical when responding to a client with physical issues include:

• Avoid segregating or stigmatizing any users.

• Make the reach to all frequently accessed components comfortable for any seating or standing user.

• Allow the user to maintain a neutral body position.

• Provide a clear line of sight to important elements for any seated or standing user.

• Provide space for the use of assistive devices or personal assistants.

• Use reasonable operating forces.

• Minimize necessary sustained physical effort.

• Accommodate variations in hand and grip size.