Which of the following is true regarding the clean and jerk exercise?

The clean and jerk exercise involves a series of coordinated movements where the lifter elevates a barbell from the ground to their shoulders and then overhead. One of the key aspects of this exercise is that the barbell should stay close to the lifter's body throughout both the clean and the jerk phases. This is crucial for maintaining balance, leveraging the lifter's center of gravity, and optimizing power output. Keeping the barbell close minimizes the moment arm, which allows for better control and more effective lifting mechanics.

In contrast, the other options do not accurately reflect the mechanics and principles of the clean and jerk. A wide grip is not used throughout the exercise; lifters typically adopt a more shoulder-width grip during the clean, which is adjusted for the jerk phase. Additionally, the clean and jerk heavily involves leg extension during the lifting phases as the lifter uses their legs to generate force and power. Lastly, this exercise is not primarily an upper body workout; it requires significant lower body engagement, as well as coordination of both upper and lower body muscles to achieve a successful lift.