By Nick Tumminello

Core training is always a hot topic among fitness professionals and exercise enthusiasts alike. And, usually anytime there is a hot topic in the health and fitness arena, there will be many false beliefs about that topic. Core training is no exception. That said, most fitness professionals are aware of the common false beliefs about core training that many exercise enthusiasts hold, such as believing that spot reduction (i.e., localized fat loss through specific exercise) can be achieved via abdominal exercises.

Many fitness professionals, hopefully, are aware that research in this arena not only demonstrates that abdominal exercise does not preferentially reduce adipose cell size or subcutaneous fat thickness in the abdominal region to a greater extent compared to other adipose sites (1,2), but also that the research shows that spot reduction does not occur as a result of resistance training in other regions of the body such as the upper-body and lower-body (3,4). However, many fitness professionals are unaware that they also commonly hold false beliefs about core training as it relates to posture, pain and performance.

Just as the claim that spot reduction is a legitimate training approach is revealed to be a false belief because it doesn’t line up with the relevant scientific evidence investigating it, this article focuses on four claims fitness professionals often make about core training as it relates to posture and performance, and demonstrates why these are false belief because they stand in contrast to the relevant scientific evidence.

False Belief #1 – Clients and athletes don’t need to do exercises that focus on strengthening the abs and obliques because squats and deadlifts do the job more effectively.

Since a few studies claim that multi-joint, free-weight exercises such as squats and deadlifts activate “core” muscles better than isolation core exercises, it has led many fitness professionals and strength coaches to mistakenly think that all clients and athletes need to do to strengthen the abs and obliques are squats and deadlifts.

One of the two studies that are most commonly quoted as scientific evidence that squats and deadlifts work better for training the abs and obliques is entitled Systematic Review of Core Muscle Activity During Physical Fitness Exercises. The purpose of this article was to “systematically review the literature on the electromyographic (EMG) activity of 3 core muscles (lumbar multifidus, transverse abdominis, quadratus lumborum) during physical fitness exercises in healthy adults.” (5)
First off, it important to notice that when the authors of this study say “core muscles” they’re not referring to the rectus abdominis and the obliques.

Secondly, the major findings of this review are as follows:

  • No studies were uncovered for quadratus lumborum EMG activity during physical fitness exercises.
  • Moderate levels of evidence indicate that lumbar multifidus EMG activity is greater during free weight exercises compared with ball/device exercises and is similar during core stability and ball/device exercises.
  • Transverse abdominis EMG activity is similar during core stability and ball/device exercises.

It’s clear that the results of this review certainly do not demonstrate that squats and deadlifts create more activation of the rectus abdominis and oblique musculature than exercises that focus on those core muscles, because this study didn’t even involve this aspect of the core musculature. However, what these findings do reveal is that if one is doing exercises like squats and deadlifts, one is not neglecting the deep (local) core stabilizing muscles like the transverse abdominis and the lumbar multifidus.

Additionally, the researchers of this review concluded that “The available evidence suggests that strength and conditioning specialists should focus on implementing multijoint free weight exercises, rather than core-specific exercises, to adequately train the core muscles in their athletes and clients.”

Now, if one only reads that conclusion, and fails to ask, “which core muscles did the researchers of this study look at?” one can clearly see how the results of this study has been misinterpreted and misrepresented as evidence demonstrating that squats and deadlifts create more abdominal activation that core-focused exercises directed at those specific core muscles, which it clearly does not.

The other of the two studies that often gets misinterpreted and misrepresented in the same way is entitled Trunk muscle activity during stability ball and free weight exercises. In this study, squats and deadlifts were done with loads of approximately 50, 70, 90, and 100% of the subject’s 1RM. Also completed were 3 stability ball exercises: birddog, hip bridge and ball back extension. (6)

The results of this study showed that “activity of the trunk muscles during Squats and Deadlifts is greater or equal to that which is produced during the stability ball exercises. Therefore, the researchers stated that “Squats and Deadlifts are recommended for increasing strength and hypertrophy of the back extensors” (i.e., the posterior core muscles). However, in regards to the anterior core musculature, the researchers also clearly stated that “No significant differences were observed in the rectus abdominis and external oblique muscles during any of the exercises,” which makes sense considering the fact that this study didn’t compare squats and deadlifts to exercises that are designed to activate the anterior core (i.e., abdominals and obliques) musculature.

So, once again this study demonstrated clearly the part of the core that squats and deadlifts elicit high levels of activation in is the posterior core musculature (i.e., the back extensors) when compared to other exercises that target the posterior core muscles, but it certainly does not demonstrate that squats and deadlifts activate the abdominals and obliques to a greater degree than targeted anterior core exercises directed at those muscles.

The results of all these studies should be expected since the nature of exercises like barbell squats and deadlifts are extension-based, as these exercises load the body in such a way that is driving your torso forward into flexion, therefore requiring you to constantly use your back extensors in order to 1) resist that force and maintain your spinal alignment and 2) perform the lift.

The practical take away:

Since squats and deadlifts work the heck out of the posterior core muscles, but don’t activate the anterior core muscles (abs and obliques) very effectively, squats and deadlifts should not be used to replace exercises targeted at the activating anterior core muscles (abs and obliques), but rather used in conjunction with them.

False Belief #2 – Anti-spinal movement core training exercises are superior to dynamic core exercises for strength and performance.

Since a 2015 study found that an isometric training approach was superior in terms of enhancing core stiffness, it has led many trainers and coaches into thinking that isometric exercises like planks, side planks and anti-rotation presses provide a complete core training stimulus. (7)

Although it’s certainly true that enhanced core stiffness allows the spine the bear greater loads (8) and to better transfer force between the hips and the shoulders (9), isometric exercises are only half of the core training puzzle because the torso musculature doesn’t just transfer force by limiting its movement (through isometric action), it also helps to produce force through dynamic movement. This reality is perfectly summarized by the researchers in a 2012 study published in the Journal of Strength & Conditioning Research, which stated that “Core strength does have a significant effect on an athlete’s ability to create and transfer forces to the extremities.” (10)

In other words, the core (i.e., torso) doesn’t just function to transfer force by limiting trunk movement, such as in an barbell overhead push-press where both the legs are able to work with both the arms simultaneously to drive the weight up by transferring force through the trunk via the torso musculature stiffening to prevent trunk movement, which creates a stable platform that allows the extremities to more effectively express force; the core also functions to produce force by creating trunk movement.

Simply by looking at athletes in action one cannot deny the obvious active movement role in power production (i.e., force summation) the trunk has in sporting actions like throwing, golfing, batting, punching, etc.

In the loading phase (before the exploding phase) of a tennis serve, a soccer throw, throwing a football and swinging a golf club, there is movement of the trunk, which creates eccentric lengthening (in various planes of motion), so the torso musculature can actively contribute, along with the legs and arms, to produce power.

You can also appreciate the active contribution the torso has in power production by trying this simple experiment:

First, perform an overhead soccer medicine ball throw (use a medicine ball that’s approx. 4-6lbs) in the normal fashion (as it’s performed in athletics) where you extend at your spine and hips a bit (I didn’t say go to end range) in order to allow your (anterior) torso musculature to eccentrically load. Then, compare that to an anti-extension soccer style throw where you don’t allow your spine to move at all. You already know which of the two throws will be more powerful. Not to mention, which throw will feel more natural and athletic.

Additionally, although isometric training certainly can lead to strength gains (11), the gains are fairly joint angle-specific to the trained position (11,12, 13).

As Chris Beardsley summarizes in his evidence-based article entitled Does your core training cover a full range of motion?:

“Although a transfer effect does occur from isometric exercise beyond the joint angle trained, the angle is fairly small, and certainly less than 30 degrees (Weir et al. 1995).Similar angle-specific gains in strength are seen after training using partial range of motion exercises, like half squats (Bloomquvist et al. 2014).

Full squats tend to produce greater gains in full squat 1RM, while partial squats tend to produce greater gains in partial squat 1RM. Full squats also produce good gains in isometric knee extension torques at all joint angles, while partial squats tend only to produce gains in isometric knee extension torques at open knee angles, similar to those in which the partial squat is performed.”

The practical take away:

Now that we’ve established that, in addition to its respiratory function, the trunk (i.e., core) muscles do two things in athletics (and in general function): transfer force through limiting movement and help to produce force by creating movement, you understand that a comprehensive approach to core training involves both isometric and dynamic exercises.

This isn’t opinion here; it’s based on the principle of specificity – a universal training principle, which dictates that the adaptations to training will be specific to the demands the training puts on the body. In other words, if you want to do all you can to help improve the function of the core muscles to transfer force by limiting trunk movement, you’ve got to use some isometric core exercises. And, if you want to do all you can to help improve the function of the core musculature to produce force by creating trunk movement, you’ve got to some dynamic core exercises.

A great example of an isometric core exercise for training the torso muscles to better resist rotation is a Tight Rotation with a band or cable (aka. Pallor Press 2.0):

And, a great example of dynamic core exercises for training the torso muscles to better create rotation are medicine ball rotational throws:

 

False Belief #3: Core strength plays a major role in performance, therefore core training exercises should be prioritized in programming.

A 2015 systematic review and meta-analysis (i.e., a study of studies) aimed to quantify associations between variables of trunk muscle strength, physical fitness and athletic performance and effects of core strength training on these measures in healthy trained individuals. The finding of this systematic review and meta-analysis indicate that, “Trunk muscle strength plays only a minor role for physical fitness and athletic performance in trained individuals.” The authors stated that “Core muscle strength appears to be an effective means to increase trunk muscle strength and was associated with only limited gains in physical fitness and athletic performance measures when compared with no or only regular training.” (14)

Now, this certainly doesn’t mean that the trunk musculature is not an important area to train by applying the exercise approaches highlighted in the previous section. It simply means that the benefit that trunk muscle strengthening (i.e., core training exercises) has on performance is often misunderstood and overstated by many trainers and coaches. I’m certainly guilty of this myself in the past.

The practical take away:

Although core training exercises should still be included in one’s training, as their use will be productive and beneficial, one must do so while keeping the limitations of those benefits in perspective. This also means there is likely no need to view or treat core training exercises as an aspect of one’s programming that requires any type of special emphasis.

False Belief #4: An anterior pelvic tilt posture indicates abdominal muscle weakness or under-activity.

Although it’s commonly claimed by many fitness professionals and rehabilitation professionals in certain belief circles that an anterior pelvic tilt posture is indicative of abdominal muscle weakness or under-activity, research investigating this relationship demonstrates otherwise.

First off, it’s important to understand a few facts about abdominal (and other core muscle) activity during standing, walking and lifting an external load.

  • During standing and walking the trunk muscles have been shown to be minimally activated (15).
  • During walking the rectus abdominis has been shown to have an average activity of 2% maximal voluntary contraction (MVC) and external oblique 5% MVC (16).
  • During standing, “active” spinal stabilization has been shown to be achieved by very low levels of co-contraction of trunk flexors and extensors, estimated at < 1% MVC rising up to 3% MVC when a 32-kg weight is added to the torso. (17).
  • With a back injury it is estimated to raise these values by only 2.5% MVC for the unloaded and loaded models [18].
  • During bending and lifting a weight of about 15 kg, it’s been demonstrated that trunk muscle co-contraction increases by only 1.5% MVC (19).

With the above realities in mind, it’s highly unlikely that abdominal/core muscle “under-activity” is an issue for most people, regardless of their posture, given that normal activities of daily life do not require the trunk muscles to be very active in order to stabilize the spine during normal daily activities to begin with.

In regards to the common claim that an anterior pelvic tilt/ lordotic lumbar posture means the abdominal muscles are weak:

The results of a 2000 study looked at lumbar lordosis and pelvic inclination in adults with chronic low back pain found that “the magnitude of the lumbar lordosis and pelvic inclination in standing is not associated with the force production of the abdominal muscles, in patients with chronic low back pain.” (20)

Another 1987 study, which used healthy adults, examined the relationships between measurements of lumbar lordosis, pelvic tilt, and abdominal muscle performance during normal standing. The results of this study indicate that, “lumbar lordosis, pelvic tilt, and abdominal muscle function during normal standing are not related.” (21)

Additionally, the researchers of this study stated that, “This study demonstrates the need for a reexamination of clinical practices based on assumed relationships of abdominal muscle performance, pelvic tilt, and lordosis.

It’s important to note that this sentiment is echoed by the researchers of another 1996 study that examined lumbar lordosis and pelvic inclination of asymptomatic adults, who stated that “The use of abdominal muscle strengthening exercises or stretching exercises of the back and one-joint hip flexor muscles to correct faulty standing posture should be questioned.” (22)

The practical take away:

As it is with performance, core strength as it relates to posture is often misunderstood and overstated. Core training exercises should still be included in one’s training to improve trunk muscle strength, but there is likely no need to give these exercise special emphasis based on one’s posture.

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