We have all heard our training partners tell us to "get mad at the bar" when egging us on to make ever-bigger lifts. It works. Indeed, in order to get the most out of ourselves physically, we must get our state of arousal to an ideal level. But what is that ideal level? How does our arousal level affect our performance? Well, in the grand tradition of my old economics professors, I will try to explain this graphically.
Source: Fitness Life Nutrition