Which progression represents the introduction to rotary breathing in freestyle?

The introduction to rotary breathing in freestyle is effectively represented by the roll breathing progression over a distance of 15 yards. This progression focuses on teaching swimmers to turn their heads to the side while exhaling and inhaling, promoting a smooth and rhythmic pattern that is essential for freestyle swimming.

By practicing roll breathing, swimmers can begin to understand how to coordinate their breathing with their strokes, allowing them to maintain a streamlined position in the water. This technique is crucial because it helps swimmers become comfortable with the movement of rolling their bodies while still being able to breathe effectively, laying a strong foundation for the more advanced skill of rotary breathing, where the entire body is engaged in a rhythmic manner.

Other options, while they may include elements of breathing or rolling, do not specifically focus on the transitional stage of rotary breathing as effectively as roll breathing does. For instance, the log roll introduces body positioning but lacks the breathing component, rotary breathing is an advanced technique, and rhythmic breathing spans a longer distance that may be too challenging at the initial learning stage.