Bowing practise or prostrations are an extension of formal practice and yet another way to cut off all attachment to thinking and "just do it". Prostrations could be likened to the 'emergency measure' for clearing the mind. They are a very powerful technique for seeing the karma of a situation because both the body and the mind are involved. Apart from being an energetic and dynamic form of meditation, prostrations also bring great health benefits.
Bows are a gesture of humility. We do not bow to another, but rather in the face of the 'other'. On the Buddhist altar is a figure of Buddha, this is the other. Bowing acknowledges the other, but not as something separate. The bow, and prostration come from the most profound depths of our aliveness.