The Ideal Body or, the body of the idea

What is the most fundamental property required for movement of the human body? Ideally speaking, without this one element there would be no ability to move. There are obviously external forces like gravity or perhaps a mass with more force and energy that when coming into contact with can also move us. The second external force, the one with the larger energy, can move us because it introduces an imbalance that exceeds our balance. The only trouble is that we are not fundamentally dependent upon this force to move us, IE. we can somehow move on our own to avoid these "external attacks". The first force, gravity, is almost the opposite of the violent external force in that it is wildly consistent. Imagine a perfectly balanced lamp. It is only described as perfectly balanced because it is working with the force of gravity to remain upright. They complement each other. Since gravity seems unwilling to change what element of this lamp would we need to alter to generate movement? Until the lamp can internally create imbalance it will remain indistinct, immobile and dependent upon external forces. I claim that the ability to internally imbalance, (distinguish, direct) force is the fundamental property required for movement. The body is unique not because it is distinct from another nature (external forces) but because it is distinct from its own nature. Realizing the implications of this could dramatically change things. I may be wrong, its hard to decide.