Complete development and intellect grow in tandem
Never try to position or exercise an infant or young child. Their own developmental needs will propel them into the proper movement. Even if a child has been erroneously strapped into a contraption, the best thing you can do now is to pare down their clothing for proper movement (take off the shoes and socks, for goodness’ sake) and clear plenty of space in the room. Massage will also help.
You know that the “milestones” of movement towards walking are only approximations, right? Children learn to move their bodies in different ways.
But it is absolutely crucial that you provide space for them to move. This includes making a Montessori bedroom with a floor bed or low bed, so they are not constrained at night. I have seen legions of adults with various back, neck, and hip pain because they have been trained to lie in their beds in a plank-like manner without moving their bodies to obtain maximum comfort, something that comes naturally to infants.
Montessori beds: I’ll do another post, but these have no rails or anything above the head. I know there is nothing much for anyone to sell with these simple beds, apologies to the retailers.
You will notice that your child wants to do things independently. This natural drive must be facilitated by parents through management of the environment — a glass coffee table must be taken away, for example, instead of the child being kept from the room. It is impossible to teach the properties of glass to a child — it is quite difficult to instruct adults in such things, they merely understand it will break.
As soon as your child wishes to help you with a task, please let them do it. It will happen before adults believe the child is ready.
Creating such simplicity should be easy, but the world is full of advertising!