Properly done... bodyweight calisthenics exercise will develop a strong, lean and athletic body that actually performs as good as it looks. In conclusion... When working on abs, the best way to use this piece of equipment and can be quite expensive, especially if they are in good physical shape. Some stomachs have a small curve, and all the crunches in the world won't change that. However, the exercises and equipment discussed below will help tone, strengthen and define your abdominal muscles. Also do an assessment of your comfort level with different types of ab exercisers and equipment. One of the most effective exercises for working those abdominal muscles. To do the exercise correctly, lie on a mat and press your lower back flat. Put your hands beside your head. Tighten your abdominal muscles and raise your trunk off the ball to about a 30-degree angle. Return to the original position with your back fully extended on the ball. Tighten your abdominal muscles and raise your trunk off the ball to about a 30-degree angle. Return to the original position with