Rob Redmond has a very good article on gravitas in karate, on this 24FightingChickens site. Here is an excerpt. It's well worth reading.
The Winner Has Gravity
by Rob Redmond - March 25, 2009
Most advanced karate players can observe two people in a sparring match and tell you who is going to win as soon as they see the match begin. They are looking for signs of one of the players possessing the power to pull or push his opponent. In most matches, one person will advance aggressively while the other retreats in reaction to him. Sometimes, the more powerful player retreats and pulls the less skilled person along with him. Either way, this gravitational effect of the more powerful player upon the weaker is objectively observable and is an effective way to predict the outcome of most karate matches.