I believe I already commented on another of your posts, but I'd like to suggest switching to a larger paper. Staying in a sketchbook can be constricting and you'll commonly see situations where you'll cut a limb short or resize one to fit in the page, which can make things disproportionate or unclear. It is also easier on larger paper for the range of motion, because you can move your arm around more and create bigger curving motions with ease. One of the widely preferred options is called newspaper, you can buy a nice large pad at most art stores! Hope that's helpful.

The curved structure lines on the arms and legs of drawings 1 and 2 are excessive and unnecessary. In general, there are a lot of lines that don't contribute to the motion or form of the figure, so try to simplify and take your time thinking and placing lines more strategically. I struggle with that, too. Other than that these are amazing!