Final answer:
The key element of the kettlebell swing is the hip movement that generates power through hip extension, with a focus on maintaining a flat back and engaged core while swinging the kettlebell.
Step-by-step explanation:
The key element of the kettlebell swing exercise involves the dynamic, explosive hip movement. This movement is driven by the powerful extension of the hips and involves swinging the kettlebell from between the knees to chest height or higher. During the kettlebell swing, it's critical to maintain a flat back, keep the core engaged, and use the hips to generate the force for the swing, not the arms. The procedure described, involving tying an object to the end of a string and swinging it in a horizontal circle, is analogous to the kettlebell being swung by the arms; however, the dynamics of human biomechanics and the purpose of the kettlebell swing differ significantly from the rotational inertia experienced in the string and object scenario.
Proper form is essential to prevent injury and to maximize the workout's effectiveness. Therefore, practitioners are encouraged to focus on the hip movement, with the arms acting primarily as a guide for the kettlebell rather than the primary mover.