There's something about passive movement...

The recognised (funded) stand-alone clinical status for therapeutic methods of passive movement has become increasingly threatened in recent times as the preference for active treatment (specific exercise) gains hold. This is in part due to the equivocal results for clinical trials of passive movement, queries regarding its cost-benefit and negative findings for many of the fundamental claims and recommendations of its clinical process. Linked to these issues has been the profession's difficulty in demonstrating plausible science-based mechanisms for anything more than transient effects. The present proposal is that the manual application of graduated oscillatory tensile loading to healing (or unhealed) soft tissues in the form of passive movement could facilitate optimal repair and tissue integrity (and so protection against subsequent 'stress'). The mechanism depends on the intrinsic ability for non-excitable connective tissue cells to 'sense' mechanical stimuli and to transduce mechanical into chemical signals. This leads to gene transcription and subsequent adaptive remodelling of the extracellular matrix (ECM). An outline of these events is given, emphasising their dependence on the effective interplay between internally (cellular) and externally (matrix) generated mechanical forces. In principle, it ought to be possible to investigate the proposal and other clinical passive movement issues using modern soft tissue imaging and biological techniques with suitable human subjects and animal models. (C) 2010 Elsevier Ltd. All rights reserved.