Part I – The Model
The Wheelchair Transfer Model describes wheelchair transfers as the combination of three factors of:
- Strength – The amount of mechanical ability of the person to willingly move parts of his or her body as desired.
- Flexibility – The degree of passive body positioning available in the person’s body.
- Technique – The level of technical ability of the person to move his or her body.
Strength is not just a measure of muscle capacity. It also includes considering the muscles that are available for use. A person with a high level of spinal cord injury has fewer muscles to draw upon then a person with a low level of spinal cord injury. Therefore, he or she has a lessor amount of strength. The presence or absence of pain effects the amount of strength available.
Flexibility takes into consideration the presence or absence of muscle spasms as well as joint mobility. A person with spasms is less flexible than a person without spasms.
Technique is a measure of inherent and learned body movement. It is made up of acquired skill and also the person’s ability to effectively move his/her body as desired in terms of coordination, speed, and accuracy of positioning.
A transfer is the result of all of these three factors working together to some degree. A person who is lacking in one or more areas needs make up the difference in the other area(s). For example, a person who lacks strength needs to make up the difference with flexibility and/or technique. A strong person may need less technique and/or flexibility. A person with great technique may be able to get by with less strength and/or flexibility.
The immediate goal of a transfer is to create a successful outcome in a safe manner. The result of transfer training should be to increase the person’s ability to repeatedly create successful outcomes while also minimizing risk. Depending upon the individual, one or more of the components of the Wheelchair Transfer Model should be the focus of his/her training to create the greatest impact.
The least understood component of the Model is Technique. Technique is the application or expression of certain physical concepts. Every person will apply the concepts in a different manner, but the underlying dynamics don’t change.
I have categorized five main sets of Wheelchair Transfer Concepts (The 5’s) involved in bodily transfers. Understanding how these concepts work and can be utilized is key to creating effective transfer technique.
Swing – A person who uses his (or her) arms to transfer creates a swing where his arms are the supports and his Center of Mass is the seat. A swing can move forward and back between its supports and also from side to side with the application of force. It can travel in an arc. The force of gravity pulls it to the middle of the supports. Therefore, gravity must be overcome to bring the person completely from one side to the other.
For example, when transferring from a wheelchair to another seat, the Leading Hand (forward support) rests on the target seat while the Trailing Hand (rear support) rests on the person’s wheelchair. The person’s butt/hips (Center of Mass more or less) is forced to move laterally along the line or arc created by the two hands.
See-Saw – The person’s arms and upper torso create the fulcrum. The surface or structure that her hands rest upon or grip form the base of the fulcrum. And the person’s head and lower body form the opposing sides of the See-Saw (levers). When one side goes down, the other side tends to go up (a body is not a stiff board, but the lever principal still applies).
For example, assume a transfer from a wheelchair to a higher seat. In this case, the transfer follows the same procedure as described above, but the person’s butt must also raise to a higher elevation. By leaning forward and dropping down with her upper body (See), she will reduce the force required to raise her butt higher (Saw).
Generally speaking, wheelchair transfers involve moving the person’s Center of Mass (butt/hips) from one stable position to another. Once the butt/hips are properly situated, the other body parts can be then moved to their desired position.
Sit n’ Spin – Some transfers involve an arcing pivot movement. There are times when the person’s feet and legs form the axis of this rotational movement. While his legs may (or may not) bear the weight of his body, having them resting on the ground reduces the total body weight that will have to be transferred. As the transfer occurs, his feet will rotate on an axis. On most surfaces, minimal friction is created, but significant weight can be reduced.
Another example is when the person is sitting on the ground with her knees pulled in tight to her chest with an arm. She uses her other arm to generate a spin allowing her to face another direction in order to initiate the transfer.
Slide – When dealing with a smooth continuous surface, it may be easier for a person to slide his body along the surface as opposed to lifting it up, over, and down. A slide board takes advantage this concept and can be used to create a physical bridge between the person’s wheelchair and the target location. Another example is when a wheelchair user scoots (slides) her body forward to the front of her wheelchair. This change in location reduces the distance of the subsequent transfer.
Structure – Effective wheelchair transfers take advantage of the person’s skeleton to create stability, support, and positioning even if his or her muscles are not actively being engaged or are weak. The concept is to align the bones in such a manner that they either support the body or influence its movement/ positioning as desired. For example, assuming sufficient flexibility, many wheelchair users are able to swat with the majority of weight supported by the legs and feet without using any lower body muscles. This position can be used as part of a transfer.
This concept includes situating the body to provide the greatest mechanical advantage, balance, and least amount of stress on muscles, tendons, and joints. For example, arms that are spaced shoulder width apart create the most effective positioning for both pulling straight up (pull-ups) and pushing straight down (dips). Arms that are either too close together or too far apart increase the difficulty of the transfer.
The twin ultimate goals of transfer training are to make wheelchair transfers as easy as possible and to expand the universe of transfers that can be successfully made. The Wheelchair Transfer Concepts of Swing, See-Saw, Sit n’ Spin, Slide, and Structure are methods to accomplish these goals. They are the underlying concepts that make up successful transfer techniques. Different people will use differing techniques in accordance with their Flexibility and Strength as previously noted, but the transfer concepts are universal.