Medicine-Ball Russian Twist

START: Sit on the floor with your knees bent and your feet flat. With both hands, hold a medicine ball. Your arms should be straight out in front of your chest. Lean back so your torso is at a 45-degree angle to the floor.

MOVEMENT: Brace your core and rotate to the right as far as you can. Keep your feet flat on the floor and your belly button facing forward. Pause, then reverse your movement and twist all the way back to the left as far as you can. Do this for 30 to 60 seconds.