Swimming's book of the five rings

When I sat down to write Ring Four: The Book of Butterfly, I knew I was stepping into dangerous territory, not just because butterfly is a brutal stroke, but because it exposes you, and for right or wrong people have strong opinions about it. It might be the most revealing stroke of them all. You can’t fake it. You can’t hide behind endurance, or muscle, or even willpower. If your rhythm is off, if your timing falters, the water tells you immediately.