Forms of tacit knowledge?

The philosopher-chemist Michael Polanyi was very interested in what he called the "tacit dimension": forms of knowledge that can be performed but not articulated.  The classic example is riding a bicycle, which is almost impossible to put into words, and can only be taught by actually putting someone on a bicycle.  Tacit knowledge is also called know-how, as opposed to know-that, which is knowledge that can be broken down into propositions (The sky is blue, the sea is green, and so on).

Talking to a friend today, I found out something interesting about the forms that this tacit knowledge can take.  Now, typically a skill like tennis or swimming (or riding a bicycle!) isn't forgotten, even when one doesn't do it for a while.  In a sense, this is because this know-how is stored not in terms of linguistic propositions but in our muscles; this is "muscle memory." 

But my friend told me that he once ran 11 miles after a long time and then ended up really sore!  I asked him how  he managed to run that distance after such a long gap.  He said that if you had done that sort of thing before (run long distances, that is), you could always do it again, howsoever long the gap.

This was an interesting claim.  The know-how he was referring to wasn't just the art of running -- although it was that too -- but stamina.  In other words, muscle memory is also about stamina, and not just technique.  I thought that was pretty interesting.