She doesn't slide the rear foot nearly as early as the clip by the op. It tends to come off the ground or slide a little right before if not at contact. Some other people have pointed it out to me and I just said I wan't worried about it right now, she's been killing it at our last 3 tournaments and at practice. As inconsistent as she has been in the past and using the advice I received on here over the winter, I'm just giving her a ton of bp and leaving her alone as long as what she's doing is working for now.
That's when Correa's rear foot is moving (and may as well be off the ground). Right before, or at, contact is when the component of force downward (weight, really) through the rear leg should be at it's smallest so I don't see how it hurts much. I understand the physics of it, for the most part. What I have trouble with is understanding the physiology and biometrics that most efficiently put those physics to work, and even more so- how to best teach it to my DD.