>>4424
It is actually not necessary to use the dynamic lines as an exact blueprint fur how the limbs should look.
Note that the arms, fur example, have natural curves and the ways in which a pose changes the way those curves behave does not lie in whether the furearm and upper arm bend, as they themselves are not that flexible, but the way in which the joints of the arm behave.
In other words, the limbs keep the same curves, no matter whether one is standing, throwing, running or walking, because the underlying structure is the same, that being the muscles, but different actions, which are caused by joints altering the relations between those muscles, sometimes cause different curves to be emphasized.
The limbs themselves don't curve. The line is there to show the basic motion of the limbs along with the direction of each of its parts without the need to individually draw the relations between them. It is basically a further simplified version of the simplification of the limbs to basic shapes, with the key difference being that instead of volume being depicted, the main goal is just to show direction and motion, upon which you can then expand.
The lines are not meant to be stand alone. You draw the simply line to indicate the motion, then you layer on it the simplification with basic shapes and then you refine it.