Q: Is it possible to isolate your upper abs from your lower abs during training? My friend says you can’t, but I’ve read that you can. Who’s right?
A: To a certain degree, you’re both right. On one hand, complete isolation of any muscle is virtually impossible. The human body is designed to function holistically and supporting muscles enter into the performance of almost every exercise you do. When it comes to trying to isolate parts of the same muscle, the task becomes even more difficult. This is clearly the case with the abdominals.
Contrary to popular belief, the rectus abdominis isn’t a group of independent muscles. Rather, it is one long muscular sheath running from just below your chest bone (i.e., sternum) down to your pelvis (i.e., crest of the pubis). Thus, the upper and lower abdominals are not separable; you can’t train one part without affecting the entire muscle. Every exercise you perform will work both areas of the muscle complex to some extent.
You can, however, selectively target the lower or upper abs, based on your choice of exercises. Movements where you bring your torso down toward your pelvis (such as the crunch) place more emphasis on the fibers of the upper abdominal region, while exercises that require bringing your pelvis up toward your chest (such as the hanging leg raise) stress the lower portion of the abs. Here’s a brief rundown of how to maximize results in this regard:
When executing movements targeting the upper abs, focus on pulling your chest down toward your hips. In order to prevent the activation of your hip flexor muscles at the expense of your abdominals, your knees should be bent, with your lower back pressed to the floor throughout the exercise (your thoracic spine has a range of motion of about 30 degrees so it’s a fairly short movement). Keep your chin tucked and place your hands across your body – not behind your head. There is a tendency to pull from the neck when your hands are behind your head, especially when your muscles fatigue. This not only reduces stress to your abdominals, but also can cause strain to your cervical spine.
When performing movements targeting the lower abs, you must raise your pelvis up toward your stomach – not simply raise and lower your legs. This is a tricky proposition because the pelvis has a very limited range of motion and if strict attention is not paid to proper form, your hip flexors will tend to take over during exercise performance. You, therefore, must attempt to exert maximum effort to each contraction, forcing the lower portion of the abs to execute the movement.
Also, in order to effectively target one area as opposed to the other, it’s essential you develop a strong mind-to-muscle connection with abdominals. You need to “feel” the movement in the proper place during performance. Thus, concentrate on the desired region of the abs and channel your energies into contracting that portion of the muscle. Otherwise, you’ll ultimately fail to fully activate the target zone.