Which two strokes have the same hip action and undulation?

The correct choice highlights that both the butterfly and freestyle strokes exhibit similar hip action and body undulation. In both strokes, swimmers employ a rolling motion involving the hips, which is crucial for maintaining a streamlined position and generating forward propulsion.

In butterfly, the undulation is often more pronounced, as swimmers create a wave-like movement starting from the chest and flowing through the hips to the feet. This movement aids in the arm recovery and helps maintain momentum. In freestyle, while the undulation is less dramatic, it is still present. Swimmers rotate their hips as they alternate strokes, contributing to a more effective reach and pull phase.

The alignment of hip action and undulation in these two strokes allows for efficient breathing, as swimmers can time their breath with the natural rise and fall of their bodies in the water, optimizing their oxygen intake while minimizing disruption to their stroke rhythm. This synergy between hip action and undulation is a key component in mastering both strokes effectively.