Definitive Abs

A Scientific Approach To a Six-Pack

Definitive Abs - A Scientific Approach To a Six-Pack
By David Peck, PhD

The avenue to amazing abs is cluttered with training evangelism and everyone has his own opinion, technique or idea about how to best train this often troublesome area. So, how can we find what exercises work best to tone and tighten the total mid-section? To weed out the flack and uncover what really works in the elusive world of abdominal training, we turn to the reliability of scientific research.


Your abdominal area consists of four separate muscle groups. The transversus abdominus lies innermost and keeps your insides, well, inside! The internal obliques run from your pelvis diagonally up to your sternum, while the external obliques lie atop the internal guys and help you bend, twist and turn.

Outermost is the rectus abdominus, the muscle we lovingly call our “abs.” Originating in the pelvis and attaching to the sternum, the rectus abdominus supports the spine and allows us to bend forward. Bands of connective tissue run across this single muscle, and create the desired “six-pack” appearance most evident in a lean, toned individual. While certain movements can target different areas of the rectus abdominus to a greater degree, there’s really no such thing as the “upper” and “lower” abs; the entire muscle gets stimulated each time you perform an exercise.

Science and a Six-Pack

Although you can’t willingly divide your rectus abdominus in half like Moses did the Red Sea, you can choose exercises to work it wisely, and some exercises are scientifically superior to others. In a recent study conducted at the University of San Diego, Calif., 31 subjects were tested using an electromyography machine (EMG). Electrodes were attached to both the topmost and bottommost sections of the rectus abdominus, atop the obliques, and on the hip flexors. “When a muscle contracts, it sends out an electrical impulse which is read by the electrodes, and in turn computes into a reading,” explains Dr. Peter Francis, Director of the Biomechanics Laboratory and conductor of the study. “It’s this reading that tells us which exercises are eliciting the most work from the different areas of the abdominal region.”

The willing subjects performed 14 repetitions of 13 different exercises, and a ton o’ crunches later– 182 to be exact— the results were in. While all the exercises tested elicited lots of work from the rectus abdominus– good news for those of us who are six-pack obsessed— three exercises beat out the rest when it came to total abdominal recruitment: The Roman chair leg lift, the bicycle crunch and the reverse crunch. “These exercises all put your pelvis in an unstable position, causing all of your abdominal muscles to contract to help stabilize it,” explains Francis. “This happens when you hang in space or pick your feet or hips up off the floor. Add to that a body rotation, and you generate even more muscle activity by recruiting the obliques to a greater degree.”