It's very important to my wee man that he is able to "boing" like a bunny rabbit. You don't need an excuse to start jumping you just do it because it's good fun. For a while he has understood the concept of jumping, bending and stretching at the knees and you usually got a kind of shuffle forward. Then one day he does it properly. Now the feet leave the floor! So maybe not every mothers marker of their child's amazing development but it does it for me!