I had a lot of fun doing this anatomy study. The whole model took me about 12 hours, I'd say. I went with a semi realistic sketchy style, trying to naturaly incorporate brush marks to enhance the forms liveliness.
The pose reference comes from this awesome free reference photo pack by Mels Refimages
https://www.artstation.com/marketplace/p/ryL92/free-artistic-nude-study-ginger-girl-with-staff-870-photo-references
The hair and face I mostly improvised