Electric Wheelchair Ergonomics & Components
Important factors to consider when selecting a wheelchair are ergonomics:
Wheelchair Leg Rests
Maximum comfort and safety are attained when leg rests are properly used to support the legs and feet. The bottom thigh area should be fully supported by the seat while the sole of the feet are being supported by the footplate. Discomfort and poor posture are caused when the legs and feet are left hanging without support or when the footplate is adjusted too high. When legrests are not properly fitted, the wheelchair becomes more difficult to navigate because of improper weight distribution.
There are three typical styles of leg and foot rests:
1. Swing-away, removable footrests swing aside for easy access in and out of the wheelchair as well as unobstructed use of tables and desks. Removable footrests are useful when storing the wheelchair in a car trunk.
2. Elevating leg rests are used when better circulation is needed or there is limited mobility in the leg. They raise the foot and straighten the leg. A calf pad is usually needed too.
3. Fixed riggings are attached to the wheelchair and are not removable, but the height of the footplate can be adjusted.
Some electric wheelchairs come equipped with power-elevating legrest that is operated by a switch that raises or lowers the legrest.
An power elevating legrest brings the leg into a straighter position. This is important if you have issues about fluids collecting in the feet and lower legs, and for some amputees.
When the legest is elevated, the feet extend further forward, increasing the wheelbase, and thus the greater the space is required to turn the wheelchair around.
Wheel Drive System
Rear-wheel drive. In this configuration, the rear wheels push the wheelchair forward. This is the most common design and is the least expensive option. Front wheel drive is best for flat surfaces. The small casters in front cannot roll as easily over changes in the surface such as a small curb or high door thresholds. Some models allow you to select larger casters to minimize this problem.
Mid-wheel drive. In this configuration, the drive wheels are directly underneath the person and provides better traction. A set of caster wheels is used in the front to prevent tipping. Mid-wheel drive wheelchairs tend to rock a bit when driving down a hill. As such, they are best for people with some upper body stability. They have the tightest turning radius since they turn around their center, so are the best solution for indoor use.
Front-wheel drive. In this configuration, two large wheels are used in the front which pulls the wheelchair forward. feel from a rear wheel drive chair, and can take a little getting used to when learning to drive it. With the powered wheels in the front, you can drive up over small curbs.
There are three major types of electric wheelchair and scooter tires:
1. Pneumatic air-filled tires provide a softer ride, but need to be kept inflated. Pneumatic tires are softer than urethane tires and have greater rolling resistance.
2. Pneumatic foam-filled tires provide a stiffer ride compared to air-filled tires but will not go flat.
3. Solid urethane tires provide the quickest and stiffest ride, but will not go flat.
Tire tread also affects the wheelchair ride. Tires with very little tread turn more easily. Knobby tires with deep treads are helpful on unpaved and rougher surfaces, yet offer less maneuverability.