Start in a split squat position. Explosively bring your back knee forward as if you were kneeing someone standing in front of you. As you stand up, touch your knee to your opposite elbow using a hard rotation through the core and extension of the front leg. Return to the start for the next rep.
Basso says: This move mimics how a martial artist or fighter would throw a knee. You’re getting rotation and forcing your abs to work as hard as they possibly can. The power of torque (rotation) will fire abs more than any other exercise.