Module 9 - Manual Wheelchair

1. Stability and manoeuvrability

Apart from the client's postural and pressure management goals, other important aspects to be considered are stability and balance of the wheelchair. Stability can be a trade-off for manoeuvrability and propulsion efficiency.

For clients who are experienced wheelchair users, configure the wheelchair for efficiency and manoeuvrability to provide the optimal wheelchair propulsion pattern for upper limb preservation, as outlined in 'Preservation of upper limb function following spinal cord injury: a clinical practice guideline for health-care professionals'.

Recommendation 8

Adjust the rear axles as far forward as possible without compromising the stability of the user.

Recommendation 9

Position the rear axle so that when the hand is placed at the top dead-centre position on the push rim, the angle between the upper arm and forearm is between 100-120 degrees.

For the first time user, consider prescribing an adjustable wheelchair that can be configured to maximise stability and then as the client's wheelchair skills improve, readjust the wheelchair to maximise propulsion efficiency and manoeuvrability.

The manual wheelchair configurations that influence stability and balance may include:

• Axle position: a backward position behind the client's centre of gravity increases stability and the footprint (length of the wheel base between front castor and rear wheel) while a more forward position towards the centre of gravity improves manoeuvrability and ease of performing a wheelie to overcome obstacles and challenging terrains.
• Seat rake (also known as seat dump or squeeze): an increase in seat rake will increase the difference between the front seat to floor height to the rear seat to floor height. Stability is achieved through a lowered centre of gravity by:
  • Changing the rear seat to floor height via the vertical axle position (liaise with the supplier as methodology varies between wheelchair designs)
  • Changing rear wheel size (smaller rear wheels lower the rear seat to floor height)
  • Changing castor size (larger castors raise the front seat to floor height)

  Caution

  • Be aware that changes to seat rake will alter the back angle, requiring a reassessment of posture and balance.
  • Adjustment to the front caster angle will be required to ensure that the front castors remain perpendicular to the floor to prevent castor fluttering and breaking.
  • Each option can have positive or negative impact on the client in the overall performance of the wheelchair depending on the environment.

• Camber: an increase in camber angle of the rear wheel will increase the wheelchair lateral stability and ease of turning. Alternation to camber may inadvertently lower the axle position and increases the seat rake. As 1º of camber increases overall wheelchair width by approximately 25mm, environmental access such as doorways should be considered.
• Front castor position: the shorter the distance between the front castors and the centre of gravity, the greater the manoeuvrability and ease of access. However, this can also reduce the forward and lateral stability of the wheelchair during activities such as forward lean weight shift and transfers.
• Foot support height and style:  provide appropriate foot support height and style of support for lower limb positioning. Ensure that the shoes width fits inside the tapered frame foot support.

Click to view "25 configuration choices for effective wheelchair propulsion", produced by Michael Babinec, OTR/L, ABDA, ATP, Invacare, accessed 2008.

Read more on wheelchair adjustment, produced by Queensland Spinal Cord Injuries Service, accessed 2008.

2. Provide appropriate size and shape to suit the client's size and shape

Consider the outcome of the clinical assessments to set goals such as correct wheelchair size to the person, appropriate postural supports, pressure management, transport, wheel propulsion and manoeuvrability to determine the wheelchair frame style, rake, seat to back and front frame angle.

Download Translating evaluation measurement to wheelchair dimensions by Michael Babinec, OTR/L, ABDA, ATP

Read more on wheelchair measurement, produced by Queensland Spinal Cord Injuries Service, accessed 2008.

Select accessories that meet the client's postural and functional requirements and safety needs.

Read more on wheelchair accessories, produced by Queensland Spinal Cord Injuries Service, accessed 2008.