Many structural, behavioral, and pharmacological interventions imply that f
avorable treatment effects in musculoskeletal pain states are mediated thro
ugh the correction of muscle function. The common theme of these interventi
ons is captured in the popular idea that structural or psychological factor
s cause muscle hyperactivity, muscle overwork, muscle fatigue, and ultimate
ly pain. Although symptoms and signs of motor dysfunction can sometimes be
explained by changes in structure, there is strong evidence that they can a
lso be caused by pain. This new understanding has resulted in a better appr
eciation of the pathogenesis of symptoms and signs of the musculoskeletal p
ain conditions, including the sequence of events that leads to the developm
ent of motor dysfunction. With the improved understanding of the relationsh
ip between pain and motor function, including the inappropriateness of many
clinical assumptions, a new literature emerges that opens the door to exci
ting therapeutic opportunities. Novel treatments are expected to have a pro
found impact on the care of musculoskeletal pain and its effect on motor fu
nction in the not-too-distant future.