Lower Abs: One Simple Technique

I have long recommended separating abdominal work into exercises that focus mainly on the upper abs, such as crunches and exercises that focus more on the lower abs, such as hanging leg raises and reverse crunches.

This way you develop well-balanced abs from top to bottom.

Yet you may have heard from some trainers or read from some experts that it's impossible to focus on the upper or lower abs and that both areas are used equally whether you do crunches or reverse crunches.

This misinformation was based mainly on an older study that reported that when subjects did the hanging leg raise, muscle activity of both the upper and lower rectus abdominis (abs) were the same.

I disregarded this study as I knew from experience that their findings were false.

I know, as does anyone who has trained abs properly, that it is in fact possible to focus more on the upper or lower abs with proper exercise selection. Plus, bodybuilders had figured this out decades ago and the results that they have achieved with this practice speaks volumes of its effectiveness.

Now a new study reveals that it IS possible to focus on the upper or the lower abs based on exercise selection.

Researchers from the University of Sao Paulo in Brazil had male subjects perform the crunch and the reverse crunch while they measured the muscle activity of the upper rectus abdominis and the lower rectus abdominis muscle fibers. They reported in a 2011 issue of the Journal of Sports Science and Medicine that the subjects used more upper ab muscle fibers than lower ab muscle fibers during the crunch and they used more lower ab muscle fibers than upper ab muscle fibers during the reverse crunch. They further supported this finding with the fact that research in human cadavers shows that the different portions of the abs are innervated by different nerves.

Jim's Take-Home Message:

As we knew all along, it is possible to focus on the upper abs or the lower abs by doing exercises that emphasize each area. So be sure to incorporate a variety of exercises that focus on the upper abs and exercises that focus on the lower abs. Exercises that involve flexing the spine and moving the shoulders forward, such as crunches, place more focus on the upper portion of the abs. Exercises that involve flexing the spine by moving the hips and legs forward, such a reverse crunches, hip thrusts and leg raises, place more emphasis on the lower abs.

Since the lower abs tend to be the weaker area for most people, consider starting your ab workouts with a lower ab exercise while your abs are their strongest and not yet fatigued. Then follow with upper ab work, as well as exercises that target the obliques and strengthen the core.

Reference:

Marchetti, P. H., et al.  Selective activation of the rectus abdominis mucle during low intensity and fatiguing tasks. Journal of Sports Science and Medicine 10(3):322-327, 2011.

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