@sweber_de For this study, I use https://quickposes.com/en ( the sitting collection) I skip the one I don't want, and 'open in a new tab' the picture I want to study, so I don't have to deal with the clock.

I change the proportion, I make my drawing a bit more athletic. An exaggeration just to train muscle groups.

> can you do it just by imagination?

Yes, I can but with more errors or area sometime I don't really know how to solve it precisely. Having a ref' helps me to spot these issues.