Which propulsion method involves using both legs in a simultaneous motion?

The propulsion method that involves using both legs in a simultaneous motion is the frog kick. This technique allows divers to efficiently move through the water by bending the knees and bringing the feet towards the body before sweeping them outward and then back together in a fluid motion. This kick enables divers to maintain stability and conserve energy, particularly in confined spaces such as caverns, where precision and control are crucial. The simultaneous leg action helps in creating thrust while minimizing turbulence, making it an ideal choice for diving situations that require careful finning techniques.

In contrast, the flutter kick utilizes an alternating motion of the legs, while the backward kick is oriented towards moving in reverse. Hand pulling involves the use of the arms in combination with some form of propulsion but does not focus on simultaneous leg movement.