Question
What is postural control?
Answer
We are familiar with the term postural control. However there are some standard definitions I would like to use. I also want to promote the definition by Schumway-Cook and Woollacott, 2007, so we can better understand the constructs of postural control. The widely accepted definition is that postural control is the control of the body's position in relation to the task in the environment. When we are engaged in a task, or an interaction with the environment, we must be able to maintain our balance. In other words, we need to maintain postural stability and postural orientation. Postural stability is an automatic function whereas postural orientation is volitional. Volitional is something that we are conscious about. We can will ourselves to change our posture, whereas, something that is automatic requires a lot more conscious effort to override.
In the scheme of movement and motor functions, automatic functions tend to be reflexive. Dysfunction can be under two systems of control, reflexive and volitional. Dysfunctions do not always occur in both, but may influence the other. For example, a client in a nursing home spills most of her food because the table is too high and her body is too deep in her seat. She has postural stability and is not falling all over the place. She is firmly planted in her seat, but she may not be oriented correctly. Perhaps she cannot correct her postural orientation or change her body position due to a weakened trunk and and decreased range of motion. As another example, a person with vestibular impairment may seem fine when engaged in a stationary task such as standing in front of the sink. He may appear to have effectively oriented himself, but then when perturbations occur, such as taking a step or turning, he may not be able to control his stability and could tip in any direction. You can see postural stability and postural orientation go hand-in-hand, and together we have this concept known as postural control.
Editor’s note: This Ask the Expert was adapted from the article ‘Assessment of Postural Control in the Geriatric Population’. The complete article can be accessed here.
