There is more than one way to train your abs. The ab wall is made up of four distinct muscle groups: Rectus Abdominis (the traditional six-pack you see in the movies and which every superhero sports) - it helps you move your lower and upper body, together. External Obliques - these are the muscles stretching over your ribs (the ones that really ache if you do a lot of push-ups, fast). They help you twist your body from side to side (and throw a punch or jump over obstacles). Internal Obliques - you do not really see them, but they help bring your body back into alignment every time you twist it in one direction or another. Finally there is the Transverse Abdominis - what we so popularly call "the core". These wrap around the spine and provide stability, keep us upright and make sure we don't get back pain from our upright posture. The standing abs workout targets all four muscle groups for a performance-enhancing experience.
Extra Credit: 30 seconds rest between sets.