Our obliques are the outermost abdominal muscles. Their main purpose is to rotate the trunk and support the spine during rotation while providing stabilization to the hips and back. To hit them hard, we're going to do a Russian twist. It begins on the floor, back and heels off the ground, with a slight bend in your knees. Keep your lower half as stiff as possible. Grab a kettlebell with two hands, keeping it close to your chest at the start. Rotate your torso to the left as you reach the kettlebell to the floor, but stop the motion just before the bell hits the ground. Return to the starting position and rotate your torso to the right as you reach the kettlebell to the other side.
If you don't have a kettlebell, you can grab a dumbbell lengthwise by its two sides.