why'd you choose an American conformation structure as a reference, if you don't mind me asking? o:
American conformation GSD's actually have very, very poor structure; the 'hyena croup' makes it very hard for the breed to do it's intended job, that is, protection work or herding.

sorry, i'm a GSD nerd 8D;

I didn't think the slanted back of my reference was as slanted as some show dogs of this breed. To me it looks like his pose merely emphasizes a slanted back without having one. And as far as I know the American Kennel Society does not allow GSDs whose anatomical structure has been compromised for the sake of beauty. Just because it's an American breed does not necessarily mean it has lost it's capability to work. If I did draw a GSD with this "hyena croup" it was not my intention.

allow me to chime in months too late...

the slanted back hinders their movements, and it leads to hip joint dysplasy because of the badly posed bacl legs. german breeds had gotten that slanded back, too, for a time. even now when that extreme form is frowned upon GSD's everyhwere are most likely to need new hip joints ar ealry ages. I have seen one at a shelter with ruined hip joints at the age of 1 year...

I grew up with one GSD, bred from a line where breeders still looked for them dogs being healthy and capable, not following some curious sense of beauty, and when she died at the age of 14 there was no sign of that illness ever. so this problem is a new one, sotosay, but it looks like it won't go away anymore no matter what.