That's not supposed to be a backward knee - it's the ankle, and ungulates like Horses run on their toes, so that other joint is the toe joint.

As someone who's heels never touch ground IRL - running is actually quite fast and easy, but you throw your weight really far forward (As though sprinting), and the toes remain parallel to the ground. It never extends as far forward, though.

I was joking aboiut backward knee, I know the anatomy. It was a reference to an old ..90s? sci-fi movie about alien invasion. Description of human-disguised alien with "bird" legs included feature "he actually got knees backward"

I know about toes, though in your case you use both toes and balls to support weight, hooved animals have only a toe with solid padding consisting of hoof's sole and frog. Apparently horses _do_ extend front hooves that way. It may depend on ground, and may related to instinctive preservation of hoof integrity. Reference used was human running on soft (sand) ground, and their feet were in same position.

nice tied up wings. it must suck to have a dead weight like that while trying to run