hey,
Well not did any google searches or somethin but i feel the question is an interesting one..
Quartz crystal in US vibraes... rarefaction and compression
leads to
waves into the tissue...
leads to
movement of the tissues & cells...
various effects of micromassage, cavitation etc work, it changes permeability of cell membranes and thus changes direction of flow of molecules... this all workss to promote healing, increase circulation...
The heating effect of relaxation and numerous others is already existing...
So all this might happen in the tissue leading to efficacy of US in soft tissue unjuries...

These may help you...

http://rheumatology.oxfordjournals.o...ull/40/12/1331


Hope i cud help..
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