One thing it absolutely would not do, is assume a 'lying' position, perform a backflip and end up lying on its face.
Dont forget a small child has a HUGE amount of input. The reason they don't attempt a backflip and land on their face is:
A) They are not physically able. If babies had developed enough muscles they would most probably injure or kill themselves by doing something just like that (as they have no (or very little) control over them). They learn through trial and error and by absorbing everything going on around them.
In the case of my own son, it was obvious the day he discovered he had a hand and could do things with it. He would stare at it fascinated and then experiment with it, by hitting it on things and touching everything, closely followed by the discovery of 'feet' a week or so later. I am positive if his un-controlled kicking legs and waving arms had had some power he would have launched either himself (or me!) into some kind of somersault before long. (ok mabe not a backflip that perfect, but the result would be pretty horrifying).
B)They spend several months developing and discovering their own bodies and gaining strength before they can even turn over let alone hope to stand up. All the while have adults around to copy and learn from. Its also a while before they realize gravity hurts, which is probably another reason that they are born so weak. Chimp babies are stronger and are able to hang on to their mothers, but their extra strength and mobility is defined and controlled by their own instincts and the environment (humans would have overwritten this 'unnecessary' code long ago) .