The best fighters don't need a treadmill to get ripped—just the heavy bag. It's great for building powerful strikes while burning off fat in fast, intense workouts. This simple circuit is your first essential step in becoming "fighting" fit. DO IT Perform the exercises one after the other. Afterward, rest 30 seconds. Then repeat for five rounds. 1.) Five low kicks, then five high. With your right leg, kick the lower part of the bag (imagine aiming for the outside of an opponent's thigh) five times. Then kick the higher part of the bag (aim for the head). 2.) Kick the bag as described above with your left leg. 3.) Twenty punches (alternate hands). 4.) Five left hooks (swing your hand in an arc), then five right hooks. 5.) Five knee strikes, alternating sides. Wrap your arms around the bag like it was the back of an opponent's head and bring your knee around to the side to strike the bag. Note: To avoid injury, always use hand wraps and bag gloves when punching. How to Throw a Jab 1.) Start with your knees slightly bent, feet staggered, chin down, and hands raised by the sides of the face. 2.) Push off your back foot and snap the jab out quickly. The lead foot will slide forward slightly before impact. 3.) For maximum power, twist your arm in a corkscrew motion before landing.