Which of the following is NOT a common propulsion method used in cave diving?

The modified dolphin kick is not commonly used as a propulsion method in cave diving. In this setting, divers typically prioritize techniques that minimize disruption to the environment and optimize efficiency in confined spaces.

The frog kick is favored for its ability to provide strong propulsion while maintaining stability and reducing silting, which is crucial in cave environments. The helicopter turn is an essential maneuver used to change direction effectively without excessive movement through the surrounding water, ensuring controlled navigation. The backward kick, while less common than the frog kick, is also used by divers to reposition themselves or maintain a particular orientation in confined areas without disturbing the sediment.

In contrast, the modified dolphin kick, often associated more with open water and specific styles of swimming or technical diving, does not provide the same advantages for cave diving as the other techniques. It tends to be less efficient in narrow passages and may create unnecessary turbulence, making it less suitable for the careful navigation that cave diving requires.