I am not a doctor but the short explanation is that the mixture contains a
liquid and a solid phase as a gel-like substance. When movement is slow the
liquid has time to 'move' around. When movement is fast energy is supplied to
the gel, the phase changes and some of the liquid becomes part of the solid
matrix (either trapped or properly transformed/incorporated). There are other
(less mumbo-jumbo) explanations for this but this one works without too much
physics in a paragraph.

Peter P.


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