For many of us, our midsections are often the center of attention (no pun intended). Yet while this region may receive more attention than other body parts, when it comes to your workouts you should treat your abdominal muscles just like any other muscle group, which means you shouldn't train them every day. Your abs, just like your other muscle groups, need recovery time between workouts too.

How many repetitions should I perform?

As with any resistance training exercise, you ideally want the last few repetitions to be difficult to complete. When performed correctly, 10 to 25 repetitions for one to three sets of abdominal exercises provide a more than adequate training stimulus. If you can perform more than 25 repetitions of an abdominal exercise, you are most likely performing the repetitions too rapidly or with improper form.

How can I make abdominal exercises more challenging?

You can increase the challenge and intensity of abdominal exercises by using added resistance, moving more slowly or performing the exercises on a slant board or exercise ball so that your head is at a lower elevation than your legs.

What abdominal exercises are most effective?

For a list of the best and worst abdominal exercises, check out this ACE-sponsored ab study.

Are there exercises that specifically target the lower abdominals?

Based on electromyographic (EMG) activity recorded during the performance of various abdominal exercises (e.g., crunches, reverse curls, leg lifts), individuals generally appear unable to differentially recruit the "upper" and "lower" abdominal muscles. In other words, individuals cannot trigger a contraction in one specific area of the abdominal muscles (either the upper or lower abs). Despite the common misconception among many fitness professionals and exercise enthusiasts, EMG data suggest that the upper and lower rectus abdominis act as a continuous sheath (i.e., one large muscle group).

Why then do certain exercises feel like they work my lower abdominal region?

Contributing to this confusion is the fact that during certain abdominal exercises (e.g., leg lifts or other "hip flexor" exercises), individuals experience localized muscle fatigue and discomfort in the lower abdominal region. This situation occurs because the primary muscle used in hip flexion, the iliopsoas, originates deep below the lower portion of the rectus abdominis. The key point to keep in mind is that the phenomenon of local muscle fatigue and discomfort should not be misinterpreted as specific recruitment of "lower" abdominal muscles.

Why is it important to train my abs?

While the thought of touting a toned midsection may be motivation for some, it is important to understand that a strong midsection serves a much higher purpose than just being easy on the eyes (although that doesn’t hurt).  Strengthening the abdominals is essential for maintain good posture, alleviating lower back pain, preventing injuries, and improving performance in other athletic pursuits.