When you come right down to it, humans are lousy at swimming. It’s not our fault—it’s simply fluid dynamics at work: The more fluid we’re in, the less dynamic we are. That’s why it’s so amazing to watch a practiced swimmer glide through water. How do they do it? It’s more than physical fitness: Their technique is nearly flawless. In this article, I’ll show you how a few minor adjustments can pay big dividends in terms of speed, power and energy expenditure in the water.