Weight Obsession
the way weight shifts when you move, how it can betray intention and speak volumes about the person.
In martial arts, dance and gymnastics (to name a few) you can tell an impending movement based on the way a person steps, where they put their weight and their movement frequently depends on the precision of those few subtle things.
…In art, the concept of weight can convey the motion of the figure even when they are frozen in time.