Her stand-to-sit is making good progress too! In the beginning, she wouldn't bend her knees at all. Her first PT said it was because Allie didn't trust herself enough not to fall if she unlocked her knees. She still sometimes hesitates before actually sitting, but she does it!
A major plus-side of all this exercise is that she seems to understand what "sit" and "stand" mean and she does them basically on demand.
Here are some pictures of her today. (left) Allie bundled up for a brief morning walk. (right) This was taken shortly before she flipped out and declared that she would not be wearing her helmet tonight.