The quick rotational movement of your body during these punches is a great way to work your abs, get your heart rate up, and help whittle away your waist.
How to do it: Start standing on guard, facing the side, with your left foot forward. 'Jab' your left arm by punching straight front, palm facing down, elbow out to the side, without locking the joint, then quickly return your arm back to on-guard position. Next, do a 'cross' punch with your right arm: rotating your right hip forward and lifting your right heel off the ground, punching your right arm straight front, rotating fist palm down, bringing elbow out to the side, without locking the joint. Then 'jab reach' your left arm up to the ceiling, keeping your hand in a fist, and then repeat the jab reach with your right arm, turning your right hip forward as you punch up. Put these 4 moves together as quickly as you can, and repeat the sequence 10 times in total on the left side, then 10 times on the right side.
Bonus tip: Be sure to turn your hips and your heels into each punch. Your abs work to control the movements of your lower body and you will get more out of each move if you work the body as one unit.