We've gotten to the point where the books are higher than Valentine is tall, and if I put the thinnest book I can find on top of the pile, she can no longer lift her leg up high enough to step back onto it. As it was, I discovered, occasionally she was stepping onto the side of the pile a books and then setting her other foot onto the top. So kind of cheating by two or three inches.
So, anyway, if I set that slim book on the top, she cheats all the time or tries to give up. I just can't seem to get her to jump at all. I thought maybe the problem would sort itself out the more we practiced, but it hasn't. I tried using a 24-pack of sodas box with the sodas still inside and some books underneath to achieve the same height, (since the box has a more slick side--to prevent the cheating) and she tried (and failed) a couple of times and then wouldn't try anymore, even when I lowered the height again. She didn't like that I had taken her handicap away.
I was wondering if anyone else had encountered this problem and if so, what you did to solve it. Or if you could think of something I can try to get her to want to jump up with her back legs. I can get her to jump forward onto things. But backward? I'm at a loss.