Balancing Act: Core

Wimp

: Crunch. Lie on back; support head with hands, knees bent, feet on the floor; raise and lower upper torso. Strive to decrease, then increase the distance between the rib cage and front hip bones.

Mortal: Torso twist. Stand with an elastic tube anchored under both feet, hip-width apart; grasp handles in both hands, elbows at waist; rotate upper body side to side. Challenge: Do it on a minitramp.

Buffed: FitBall leg lift. Get in a push-up position with shins on exercise ball, hands shoulder-width apart on floor, head in line with spine; lift one leg off the ball for 10-second intervals. Challenge: Lift the arm opposite the raised leg. Animal: Full-body FitBall. Lay facedown over the exercise ball, stomach on ball; try to lift arms and legs off the ground. Shoot for 10-second intervals.