Course Overview

Shear is an important consideration in wheelchair seating because it can contribute to tissue deformation, loss of position, discomfort, and pressure injury risk. In this Quick Class, Michelle Lange explains what shear is, how it occurs within wheelchair seating systems, and the common factors that can increase shear forces. The course explores how recline, sliding, increased muscle tone, dystonia, and large movement patterns can affect a user's alignment with seating support surfaces. Viewers will also learn how properly designed dynamic seating can help maintain contact with support surfaces, improve alignment, and reduce shear during movement.

Course Objectives

After completing this Quick Class, viewers will be able to:

• Define shear as it relates to wheelchair seating and positioning.
• Explain how shear occurs when body tissues move in relation to seating support surfaces.
• Identify common causes of shear, including recline, sliding, increased tone, and large movement patterns.
• Describe how shear forces can contribute to tissue deformation, friction, discomfort, and loss of seated position.
• Understand the relationship between shear forces and pressure injury risk.
• Explain how pivot-point placement can influence shear during wheelchair movement.
• Describe how a dynamic back differs from traditional recline in its degree and mechanics of movement.
• Explain how dynamic seating can help maintain contact with support surfaces and improve postural alignment.
• Understand why dynamic seating may decrease, rather than increase, shear forces for appropriate wheelchair users.