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Last month's Clinical Corner article addressed Understanding Choices in Manual Wheelchairs and focused on standard and folding wheelchairs. The article included links to previous Clinical Corner articles that detailed various aspects of manual mobility. This month, Clinical Corner will continue the discussion on manual mobility, with a focus on rigid wheelchairs.
What is a rigid wheelchair?
A rigid wheelchair is a wheelchair that has frame that is one piece. Rigid wheelchairs are ultralight weight due to their overall design and due to the materials used. There is no cross-brace in a rigid frame wheelchair, which means that the wheelchair does not fold side-to-side. Depending upon how the wheelchair is configured, the back canes may be able to fold down for transport purposes. Most rigid wheelchairs typically have a "fixed" front end, with a platform for foot positioning; however, some models of rigid wheelchairs exist that have swing away front hangers to allow ease of standing transfers while still providing the benefits of a rigid frame.
It should be noted that while rigid frames do not fold crossways, some models do permit a way to fold into a compact unit for transport purposes.
What is the benefit of a rigid wheelchair?
The efficiency of propulsion tends to be greater in a rigid frame wheelchair than in a standard or folding wheelchair for several reasons. Rigid wheelchairs typically are manufactured of materials that are lighter in weight than standard or folding wheelchairs. Their sleek design also minimizes the amount of material that is used to produce the wheelchair, which adds to the reduction in weight. Although these wheelchairs are very light, they are designed to be durable for the active user. The rolling resistance is less in a rigid frame wheelchair than in a folding frame wheelchair. A rigid wheelchair has fewer moving parts than a folding wheelchair. When an individual applies force to the handrim of the rear wheel on a rigid wheelchair, most of the energy of propulsion is directed in moving the wheelchair forward, rather than being lost in the flex of the frame, which can happen in a folding frame wheelchair. When there is greater efficiency of propulsion, less force per push stroke and fewer push strokes are required, which helps to decrease the risk of repetitive strain injury in the upper extremities.
What are the similarities and differences amongst rigid wheelchairs?
All rigid wheelchairs are tailor-made wheelchairs. They are manufactured to the specifications for an individual, including the size, front frame angle, inset, and choice of casters, rear wheels and tires.
Some models of rigid wheelchairs are adjustable, while others are fixed. Adjustable rigid wheelchairs may allow for changes in the rear axle or in the back angle. This option is good for an individual who may experience change over time and who may require resulting changes in the centre of gravity for performance. An individual who is very experienced in using a rigid wheelchair may elect a fixed rigid frame as they know the exact set up that optimizes fit and performance for them. An active rigid chair is fully welded with few parts that can be changed in position. The active rigid back canes (shown below) are fully welded and help to transfer energy directly from the upper extremities to the axles for the most efficient propulsion.
There are other differences in rigid wheelchair frames. Some are "open" frame, as shown in the photograph to the left, below; while others are "closed" frame, as shown in the photograph to the right, below, with the additional tube extending to the caster housing. Some wheelchair users prefer the additional rigidity provided by the closed frame. Some individuals who are lifting a wheelchair across their body into a vehicle prefer an open frame design as it provides more clearance once the rear wheels are removed.
Understanding what is required in a rigid wheelchair for an individual goes back to the assessment. The individual's goals, experience, stability of condition, activities, terrains, and positioning needs will need to be taken into account.
Why are there so many choices?
Even amongst one manufacturer, there are several models of rigid wheelchairs to choose from. Why so many choices? There will never be one model of rigid wheelchair that is appropriate for everyone. As we have seen, there is a difference between an adjustable rigid wheelchair and an active rigid wheelchair, which speaks to the experience level of the user and the need for potential changes in the wheelchair to accommodate changes in the individual's condition. As well, the activities the client will use the chair for, the terrain they will traverse, their transportation needs will make one model of chair a better "fit" for a client for their performance purposes. In addition, sometimes manufacturers continue to make "legacy" products, despite having products with new innovations on the market, to fulfill the needs and wants of loyal customers who love the product they have and do not want to make any switches as they want only a replacement to the wheelchair that is "tried and true" for them.
Summary
Rigid frame wheelchairs offer some choice in the type of frame – from open frame to closed frame and from fully welded to models with fold-down back canes. Some models of rigid wheelchairs provide adjustability in the rear axle while others are fully fixed. Rigid frame wheelchairs promote efficiency of propulsion due to their light-weight design and minimization of moving parts, which allows for more efficient propulsion. A thorough assessment is required in order to match the needs of clients with the products that are available on the market for optimal fit, function and performance.