This is a bit of a cryptic one; I was wondering whether English has a word (or at least a phrase) to describe the lines typically drawn on a cartoon to indicate movement? A good example is the Windows XP 'Run' icon (in the top-left):
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Gesture lines can be used to indicate gestures, so I think that is a reasonable answer. I've seen motion lines more commonly used for the example that you have given.
I don't have a good answer for you, but I've seen similar things referred to as gesture lines.
Gesture lines are lines that are energetic and catch the movements and gestures of an active figure.
The word is called 'emanata' but only used in comic books though.
These lines are called "movement lines" which is explained among other (comic related) techniques here