Step three raises the back legs to make it more difficult.

To be able to stand on its back legs and walk!

The power for the spring comes from the back legs and feet.

He was standing on his back legs, looking out at her.

It lost the use of its back legs but still tried to crawl forward.

He sort of got down on his back legs.

And a fine horse he is too, except for those weak back legs.

"How far down do you go on the back legs?"

Then it apparently felt tired, and sat down heavily on its back legs.

Seen from behind, the back legs are straight and not set too close.