My daughter is the one knocking down the other boy to get to the ball.  She was one of two girls on an all boy team, and we won 8-1, but we were not supposed to keep score.  The concept of not quitting has been successfully passed down to my children.  Not quitting is a fundamental trait that applies to just about anything that we do.  It not only is a Spartan principle (although the Spartans would have benefited from giving up their shield and spear tactics for more "modern" warfare approach) but also is something that is hard to do all the time.  Not quitting requires energy and will power, perseverance and a mission.  A solid mindset that uses competition and harnesses one's own emotions to produce a drive that is concentrated and purposeful.  So how do we get this mindset?  It starts with a sound body and soul.  Feed your body with powerful nutrition, get enough sleep, meet the right significant other, think in a positive and non-defeatist way, harness the power of friendship, workout everyday, feed your mind with positive energy, and develop a way of life that will take advantage of an age old tradition of altruism and life outside of one's self.  In the end, the most powerful non-quitter is the one who doesn't quit for his family and friends.  Countless survival stories, stories of life and death and not quitting, point back to family and friends as being the number one element that kept them alive and kicking.  Another peculiar aspect and common thread of these survivors: the ability to laugh at oneself.  Don't take yourself too seriously that is.  Having a sense of humor frees the mind of negative energy and allows it to focus on perseverance and the positive outcomes that emanate from it.  

So the solution is simple.  When you think of yourself as the smallest girl on a soccer field of boys you ask yourself one question: do you want to be remembered by your teammates as the one who didn't play, or the one who went out and knocked over the boys to get to the ball?