This powerful stroke requires a swimmer to move up out of the water and back down in a smooth, almost wave-like motion. While swimming butterfly, the swimmer is positioned on their stomach, toes pointed. They kick with both legs together (known as a "dolphin kick"), and use their arms to help pull the body forward. Both arms come up out of the water and forward in a sweeping motion that mimics — you guessed it — a butterfly.
Latchford explained that the "fly" challenges a swimmer's arms, shoulders, chest, core, back, and legs. "A common misconception with swimming butterfly is that it's all in the back and arms, but this isn't true," she told POPSUGAR.