Stand with your feet shoulder-width apart and hold the barbell with both hands in front of your chest.
Bend your knees slightly and rotate your torso to the right, swinging the barbell down towards your right hip.
As you reach the bottom of the movement, quickly reverse the motion and rotate your torso to the left, swinging the barbell up and across your body towards your left shoulder.
Continue this twisting motion, alternating sides, for the desired number of repetitions.