The stampede of two one and half year old dogs up and down the hallway at 5am is all the evidence I need of the boundless vitality of physical youth. But what I refer to isn't directly related to age. Although being young provides a great source of physical energy, a youthful outlook is the source of wonder and inspiration that spurs us to action. Independent of how many seasons we weather, a fresh perspective supplies exceptional energy when tackling a task. How many times have you been stumped working late on a problem only to have an elegant solution by the next morning without all the baggage of yesterday's thinking.
Many of the historical experiences we leverage in decision making are weighted too heavily. The conditions which made a wild idea impossible are in constant flux. A few years back there was no commercial web, and before that the Internet was an idea in the minds of researchers. If someone told you your startup would have to go head to head with Google in a few years you'd call them crazy, but now the Facebook team is doing just that with adaptive content sharing. Youth doesn't accept assumptions, it continually pushes against them.
There's more to motivation than a fresh perspective. There are times when you have nothing more than your will to rely on. You start moving and trust that energy will follow. There are aspects to discipline I dread, but I can't deny its efficacy. Discipline treats your body as a biological machine and wills it to action. Through training and conditioning our bodies respond to the whip of determination.