I found an interesting article the New York Times interesting: Can Your Brain Fight Fatigue?  The gist of the idea is a mind over matter thing – saying running mile 20 is really a mental thing vs. actual fatigue.  I had to think about this one for a while but it does make sense in a strange kind of way.  I mean it seems like  I always run better on race day than long run training days… nerves, adrenaline… and probably my brain allowing me to push myself harder because the race is the all – out effort – the reason I put in all those painful training days.  Also, when I am approaching the finish line, I’ve managed to find that last kick almost every time – even during the full marathon when I didn’t think I had anything left in me at all – I sprinted the last .2 to the finish…it really was mental at that point because my legs were screaming.  One of the researchers of this study says:

“Training is no longer simply an act of getting the muscles used to lactate or teaching the lungs how to breathe harder.” It’s also about getting your brain to accept new limits by pushing yourself, safely. “Once your brain recognizes that you’re not going to damage yourself,” Foster says, “it’ll be happy to let you go.”

When you put it that way – it is pretty logical.  I will have to keep this in mind next time I feel like I can’t go another mile…