The human body is amazing at responding to appropriate training.  If you run a workout you can gain fitness, allowing you to race faster than you have before.  That's training in a nutshell, right?  Well, sort of.  The missing element in that equation is rest and recovery.  For a workout to be "absorbed" by your body, you have to rest.  This means getting a good night's sleep and this also means having an easier training session the next day following your hard session.  Rest and recovery aren't glamorous and for that reason they're easily overlooked by serious runners trying to run PRs in high school cross-country.  And if you think about it, if you're serious about running faster, you might have to cut some things out of your social life that are taking away from your ability to rest and recover from both workouts and races.  Again, probably not what you want to hear, but the reality is that the runners who are running to their potential lead simple lives.  Go to school, train, come home and refuel, some homework, rest, then do it again.  It's a life that would make for a pretty boring reality TV show, but that type of lifestyle is what's necessary if you want to run to your potential.

Jay