Why It Works: This one makes that "speed bag" back-of-the-arm sag disappear because it targets the triceps, shoulders and chest muscles. It's another upper body move that carries the bonus of being a fantastic core tightener.
How You Do It: Sit on the floor with your knees bent and feet hip-width apart, flat on the floor. Place your palms on the floor on either side of your hips, fingertips pointing towards your toes or whichever direction you find most comfortable for your wrists. Lift your butt off the floor until it is level with your hips and your torso is parallel to the floor. Holding this "table top" position, bend your elbows to lower your butt towards the floor and then straighten them back up again.
Why It Works: It's the perfect move for toning up the front of the arms. By holding your body in a wide-legged position and your arms at your sides you really feel the work through the center and front of the arm.
How You Do It: To begin hold one end of a tube in each hand and stand with your feet on the center of the tube so your legs are wider than hip-width apart and there are a few feet of tube between them. With your palms facing up, hold your elbows out a few inches away from your body and bend your elbows until your forearms are parallel to the floor. Keeping your shoulders and upper arms in place, bend your elbows until your hands touch your shoulders. Lower to the start.