Movement and stability dysfunction--contemporary developments.

A good understanding of the control processes used to maintain stability in functional movements is essential for clinicians who attempt to treat or manage musculoskeletal pain problems. There is evidence of muscle dysfunction related to the control of the movement system. There is a clear link between reduced proprioceptive input, altered slow motor unit recruitment and the development of chronic pain states. Dysfunction in the global and local muscle systems is presented to support the development of a system of classification of muscle function and development of dysfunction related to musculoskeletal pain. The global muscles control range of movement and alignment, and evidence of dysfunction is presented in terms of imbalance in recruitment and length between the global stability muscles and the global mobility muscles. Direction related restriction and compensation to maintain function is identified and related to pathology. The local stability muscles demonstrate evidence of failure of adequate segmental control in terms of allowing excessive uncontrolled translation or specific loss of cross-sectional area at the site of pathology. Motor recruitment deficits present as altered timing and patterns of recruitment. The evidence of local and global dysfunction allows the development of an integrated model of movement dysfunction.