Human swimming relies on repeating specific strokes, each defining a unique style, to propel the body forward. In competitive settings, this includes two undulating strokes—the breaststroke and butterfly stroke—and two alternating strokes—the front crawl and backstroke. The front crawl is the fastest surface style, performed face down with alternating arm movements and a flutter kick.
Other prominent styles include the butterfly, characterized by simultaneous arm movements and a dolphin kick, and the breaststroke, which features synchronous arm movements and a whip kick without torso rotation. Specialized variations also exist, such as the head-high crawl (or water polo stroke), designed for visibility, and the sidestroke which uses a scissors kick while swimming on one's side. Each stroke involves coordinated movements of the entire body and is continuously evolving for improved efficiency and ease.