Often a specialized assessment by a wheelchair seating specialists is recommended so that sizing and positioning of seat, back, and footrests is appropriate. Choosing appropriate support surface materials and upholstery, as well as cushioning, are critical and many options exist to enhance sitting posture, comfort, and safety. Cushions may be secured to the seat and or back for comfort, and this seating system approach is often enough for those individuals who have good sitting balance and posture and who can easily move about and take pressure off of the bottom, back, and feet. For the individual who has some challenge in posture and sitting balance, the seating system can be used to improve the ability to be comfortable while sitting. This is done by creating curves or contours in the seat that shape to the body.
Special hardware is often necessary to mount contoured seats, backs and other attachments.
Pre-contoured seat and back systems can be selected when the individual has a common size and shape. Custom contouring is often used when the individual has a deformity of the back, pelvis or lower limbs. In this approach, either or both the seat and back are shaped to the person by way of special molding techniques. Custom contouring should always involve seating specialists in decision making and molding procedures. A precaution with contouring and additions of other seating components like trunk pads, hip and thigh supports, is that freedom of movement is further restricted and great attention needs to paid to relieving pressure on the skin.