접영, or butterfly stroke, is a swimming technique characterized by a simultaneous arm movement and a unique dolphin kick. Swimmers pull their arms back together in a sweeping motion while their legs perform a fluid, undulating kick. This stroke is known for its speed and power, making it one of the most challenging swimming styles. In competitive swimming, 접영 is often used in races and is one of the four main strokes, alongside 자유형, 배영, and 평영. Swimmers must master timing and coordination to effectively execute this stroke, as it requires both strength and rhythm to maintain speed in the water.