I really like your initiative, but I think for anatomy it’s generally better to understand the structure (in this case the bones) and then the forms that go on top (muscles). This would also help you learn proportions and give you a better idea on how to simplify thing (like understanding the meaning of the circles, they would represent the knee). I quite like your hands, I think with a bit more structure, you could greatly improve and add a sense of three dimensionality to your drawings. It also seems you’re trying to mannequinize the legs, maybe you could try the proko figure drawing course before the anatomy course? It would be a great starting point if you want to have very fluid and gestural drawings. Hope this helps!