I feel like there are too many enclosing lines. Rather than convey the motion, they enclose the form, somewhat taking away from the fluidity.
I think you're doing a great job using curves to convey the general shapes of the body! However, I think you should try using a line of action and some basic construction marks for the chest and pelvis to help your studies flow better
The curves are good to portray the motion. I think you might be focusing to much on the outline of the form rather than the flow. Don't be afraid to draw through the form with tapered stroke. Ignore the little bumps of anatomy and focus on the large overall movement/line
They look good! However I think you could also try to have more confidence in your lines, limiting the number of lines and placing them thoughtfully would help. Try drawing a simple pose (e.g someone just sitting, or standing on one leg), think of where the most weight falls, and try to draw the figure in at least 5 lines or less.
I think these are really solid for just a few weeks. Much better than mine. I think you just gotta bang out more hours.