b'
At first, a push is delivered from behind. One does not fall, but is destabilized, flaps the arms about to stay upright and re-establish equilibrium. This is to be expected of anyone. When a push is delivered from behind, however gently but unexpectedly, the initial response of the body to a sudden shock is once again to establish stasis.
The body flaps the arms about. We can measure degrees of arc, inertial impulse, distribution of weight and velocities of hand-movement. This is the dream-story of learning to hover in mid-air.