Looking at your drawings you seem to be making things that are very similar to what my sketches are ending up like, i felt a lot of stagnantion too and what i did to help a little, which might help you too, is actually not doing poses but going a different direction and looking at muscle and bone anatomy. I look up photos of medicinal/educational diagrams of the human body, photos of rotated ribcages with shoulders and bone on pinterest, some pose websites pecifically have muscle skins like posemaniacs. Try look up specific areas of the body if you run out of images.
This studying of actual body tissue and bones will give you a wider shape vocabulary.
As well what i think the anatomy studies have helped me with is adding weight and substance to my figures. Now my poses have some more structure besides circles and lines- which you have done and its good to keep that step in mind but it seems like you are in need of some new material to base your people off of. Hope this helps :D