Which of the following is not a step in the butterfly progression?

The butterfly progression involves a series of skill-building steps designed to help swimmers master the butterfly stroke effectively. The correct answer indicates that "Butterfly 10 yards" is not a formal step within this progression.

When teaching the butterfly stroke, instructors typically start with foundational skills such as the dolphin kick and the arm movement. The dolphin kick is crucial for developing the body undulation that is characteristic of the butterfly stroke. After mastering the kick, swimmers learn how to coordinate their arms with the legs, which is referred to as "butterfly arms."

The progression often includes drilling the stroke over various distances to reinforce technique and stamina. While it's common to practice the full stroke over longer distances like "Butterfly 25 yards" to gauge proficiency and endurance, the specific repetition of "Butterfly 10 yards" does not align with the standard progression framework typically utilized in swim instruction. This helps ensure that students focus on technique and coordination before attempting longer swims. Thus, the absence of “Butterfly 10 yards” in established progression steps highlights its role as less structured compared to other aspects of the technique.