Becoming a High Performance Person: Train your potential muscle

I once read about a man, who for unknown reasons decided to climb down a multi-story building. During his descent, as he hung from a window ledge it got dark and he could no longer see where he was going. Unable to pull himself up, he clung by his finger tips with all his might waiting for morning to come so that he would be seen and rescued. To his astonishment, at day break, he discovered that his feet were only a few inches off the ground.