I like the fluidity in your line work Steve. One thing you should keep in mind is the forms and structure of the figure. It seems like you were focusing on the outlines and in doing the the drawing lacks a sense of form overall. You should think about how the body parts fit into each other.
It is great to see there is somebody out there; thanks for your reply! So are you saying that modeling should be done concurrently with getting the gesture? Is modeling based on the lighting or on an intuitive understanding of the form? Sometimes I see a lot of latitudinal lines in quick sketches; this isn't what you mean, is it? I might go back to charcoal; that might help.
I prefer to use the words "constructing" and "building", like if you where working in a 3D program. After all, the figure is a 3D object.
This indeed needs to be considered when drawing the gesture. Even though the focus at this stage is not on forms, the gesture is being performed by the 3D forms of the body so you need to consider how and where the parts attach so your figure doesn't fall apart.
As for modeling, it can based on both an intuitive understanding of form and on the actual lighting. Personally I like to save lighting for later stages of the drawing process. At the gesture stage I focus on analyzing and understanding how the body stays balanced relative to gravity through rhythm. This is what's happening in reality. If you look at the examples in my thread I think it will be clearer.
I hope this helps.If you have further questions feel free to ask.