Had the same problem here
Try moving in real slow and a little low, then when you are close to her head, and she is still sitting, pull the treat up a little.
With high energy dogs(and jumpers
![Big Grin :D :D](/members/forums/styles/default/xenforo/smilies/biggrin.png)
) start rewarding for a little movement of the front legs, while still sitting. Don't go all the way immidiately. Highly reward the sitting and a little paws up(even if it is just an inch of the floor, or just one paw that goes up)
The key in this trick is selfcontrol first and then later the balance. And combining the two is really, really hard for our 90 mph dogs
![Big Grin :D :D](/members/forums/styles/default/xenforo/smilies/biggrin.png)
If that goes well, you can start luring your treat higher up, to get them to sit up more and more, maybe you will need to "help" by letting them lean a paw on your arm, to keep balance.
If she keeps moving away, you can try fencing her in. Put two chairs(or somthing like that) against the wall, leaving just enough space between them for your dog to sit between them. And then do what I discribed above. Because she is boxed in, there is no way for her to move, so it might be a little easier.
Hope this helps! Good luck!