3. Weighted Crunch
First lie straight on your back on a bench. Your head should be hanging off and knees and hips bent. Hold the weight behind your neck or over your face. This will be your starting position. Then, flex your waist to raise your upper torso from the bench. Remember to keep your lower back on the bench and raise the torso up as high as possible. At the top of the movement, flex your abdominals and hold for a brief pause. Slowly lie back until you are supine on the bench once again (back to the starting position). Do this 15 times during your workout.