Main Muscle Worked: Abdominals
Other Muscles Worked: None
Equipment: Barbell
Mechanics Type: Isolation 

Tips: Works your obliques. Place a light barbell on your shoulders and sit at the end of a flat bench with your feet firmly on the floor. Twist your torso to the right, then to the left by twisting at your waist only. Do not move your head from side to side. Keep your back straight and your head up. Can also be done standing or by holding a dumbbell close to your chest.