Trigger Point Therapy - Postural and Phasic Muscles

Postural Muscles and Trigger Points - Dr. Jonathan Kuttner M.D.

When your muscles are placed under faulty or repetitive loading, the postural muscles will shorten and the phasic muscles will weaken

It's often accepted that muscles that have a stabilizing function (postural) have a tendency to shorten when stressed, and other muscles that play a more active/moving role (phasic) have a tendency to lengthen and become inhibited.

The muscles that tend to shorten have a primary postural role. However, there are some exceptions to the rule that certain muscles follow the pattern of becoming shortened while others become lengthened – some muscles are capable of modifying their structure.

For example, certain authors suggest that the scalenes are postural in nature and some suggest that they are phasic.

We know that, depending on what dysfunction is present within the muscle framework, on specific testing one can find the scalenes to be held in a shortened position and tight, but sometimes when they are tested they can be found to be lengthened and weakened.

There is a distinction between postural and phasic muscles; however, many muscles can display characteristics of both and contain a mixture of Type I and Type II fibres.

The hamstring muscles, for example, have a postural stabilizing function, yet are polyarticular (cross more than one joint) and are notoriously prone to shortening.