fifth stroke

fifth stroke
 n.— «“It helps when you have a good dolphin kick. It’s called undulation. It means you have good wave motion.” That wave motion has carried Kelly to the top of the state leaderboard in just about every stroke. “If you’re good at it, it can work for you,” Scharbat said. “They refer to it as the fifth stroke. It’s something the elite swimmers have. If you’re doing it just to do it, it won’t help.”» —“Margaret Kelly, a junior, is the latest star at Ann Arbor Pioneer” by Mick McCabe Detroit Free Press (Mich.) Nov. 12, 2004. (source: Double-Tongued Dictionary)