Talk to a Zone Specialist: 800-404-8171

The Truth about Core Training

by Lisa Ziegel

In the fitness world, focus on the abdominal region has always been a hot topic. Some time in the early 2000s the spotlight shifted from focusing solely from a desire for the look of “ripped abs” to strengthening of this area, which collectively came to be known as “the core.”
From mat Pilates, to yoga with an emphasis on the core, classes, videos and entire fitness studios and gyms prominently featured core training, and it caught on big. But the concept was not without controversy. There were camps that believed that isolating core muscles was not the most effective route to building overall strength and enhancing the function of the entire body, and others who viewed it as the base of all strength and function. Specific exercises were practiced and believed to be essentials in “functional” training. Catch phrases, such as “scooping your belly in” or “pulling your navel toward your spine,” were well-worn in classes, and trainers were teaching their clients to activate their “TVA” (transversus abdominis) while performing plank exercises and the like. The idea of doing sit-ups, crunches, bicycle movements and more has been challenged as either a waste of time or even accused of being downright injurious to the spine. So who is right? Is it worthwhile to strengthen the core, and if so, what exercises are really effective? Thankfully, recent scientific research has shed more light on the subject, and the good news is that there are exercises that can effectively strengthen the mid-section and benefit the entire body, thus enhancing overall fitness and functioning. So read below to find out what you should be spending time on or avoiding in your exercise program.
Exercise physiologists needed an accurate, unbiased means of measuring muscle activity in studying abdominal exercises. Technology came to their aid in the form of EMG, or electromyography - - the capture of the electrical current generated from muscle activity through electrodes placed on the skin at the site of the muscle being tested. Researchers chose to utilize surface EMG vs. intramuscular as the latter involves inserting very fine electrode wires through the external layers of tissue to access the deeper musculature. Instead, they devised a way to infer deep muscle activity through the primary activation of the more superficial muscles. A series of exercises were examined, with Pilates-types being of particular interest since it has been around so long and has been accepted as a standard for deep-abdominal muscle training. Popular techniques used in yoga practice were studied, as well as a newer, trendier form of training: “core-off-the-floor”, or standing abs exercises. The results were compared against a standard of the customary “crunch” exercise, assuming this movement utilizes 100% of both deep (TVA and internal obliques) and external (rectus abdominis or “R.A.” and external obliques) abdominal muscles.
• Pilates
Most Pilates exercises were deemed effective in activating the external muscles involved in the anterior trunk, particularly the “roll-up” “criss-cross” (or “bicycle”) and “teaser.” However, other classic Pilates moves, such as the “hundred” and “double leg stretch,” do not activate as much of the rectus abdominis. But these are apparently still useful in that they are more effective in activating the deep transversus abdominis muscles than the former, but either way, these exercise challenged all abdominal muscles at a higher percentage than the reference value of the crunch.

• Yoga
Yoga shares many similarities in that breathing and muscle control are highly emphasized. Three yoga poses were examined, and all three were found to engage a higher than reference value level of muscle activity in both the internal and external abdominal groups. These poses included the yoga “boat” pose, the side plank, and the “dolphin” plank (using a stability ball).

• Standing Abs
Proponents of this method of core training claim that performing crunches, bicycle movements and side bends are more effective while standing. The EMG tests showed a lower level of both R.A. and deep ab-muscle activation, in fact, at a lower level than the standard crunch. But another important effect was shown to take place – the involvement of auxiliary muscle groups (e.g. the back and glutes) necessary in the development of overall body strength, function and endurance. This goes with the thinking that isolating specific muscle groups is not as “functional” as when the body operates as a whole.

So there we have it, hard evidence that some popular core exercises are more effective than others. So should you just do the ones that activate the muscles the most? Not necessarily. In order to effectively strengthen the core and protect the lower back, choosing a variety of exercises that engage all angles of the torso (front, back, sides) as well as utilizing the muscles that act on the upper torso (latissimus, back extensors) and the lower trunk (glutes) will ensure balance to avoid injury. So for example, incorporating lunges with side-sweeping arm movements, supine (facing-up) hip extensions, along with a mix of Pilates-type (hundreds, double-leg stretch), yoga (planks and side bridges) and standing ab moves (standing bicycles) would make for a well-rounded core strengthening program. Here you have a combination of isolation and whole-body movements, and both are more effective when performed together vs. one or the other.

It should be mentioned that caution should be used when performing basic crunches (a better term would be a “curl-up”) – pressing your lower back into the floor is not recommended due to stress placed on the lumbar spine, nor is fully flexing the spine as in a full sit-up, at least not on a continual, repetitive basis. And performing curl-ups and planks on a large stability ball increases the effectiveness of both.

As with any training regimen, consulting with an expert who can screen you for movement imbalances would be a safe way to begin a core training program. And learning proper form and technique are key to avoid injury. Done properly, the right exercises can lead to a trimmer, more toned mid-section (in addition to a consistent cardiovascular exercise routine and a healthy eating plan -- sorry, there are no shortcuts. The benefits of a strong core integrated with whole-body strength and endurance will make for a healthier you.

ACSM’s Health & Fitness Journal: July/August 2013 - Volume 17 - Issue 4 p. 8-15